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Healthcare 2023, 11, 658. https://doi.org/10.3390/healthcare11050658 www.mdpi.com/journal/healthcare
Study Protocol
Determinants of Acquisition, Persistence, and Clearance of
Oncogenic Cervical Human Papillomavirus Infection in the
Philippines Using a Multi-Omics Approach: DEFEAT HPV
Study Protocol
Sheriah Laine M. de Paz-Silava 1,2,*, Ian Kim B. Tabios 1,3,4,, Ourlad Alzeus G. Tantengco 1,5,6,
Fresthel Monica M. Climacosa 1,2, Clarissa L. Velayo 1,5,7, Ryan C. V. Lintao 1, Leslie Faye T. Cando 1,
Glenmarie Angelica S. Perias 1, Maria Isabel C. Idolor 1, Abialbon G. Francisco 1,2, Charlene Divine M. Catral 1,
Charlotte M. Chiong 1,8 and Leslie Michele M. Dalmacio 1,3,*
1 Multi-Omics Research Program for Health, College of Medicine, University of the Philippines Manila,
Manila 1000, Philippines
2 Department of Medical Microbiology, College of Public Health, University of the Philippines Manila,
Manila 1000, Philippines
3 Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines
Manila, Manila 1000, Philippines
4 Institute of Biology, College of Science, University of the Philippines Diliman,
Quezon City 1101, Philippines
5 Department of Physiology, College of Medicine, University of the Philippines Manila,
Manila 1000, Philippines
6 Department of Biology, College of Science, De La Salle University, Manila 0922, Philippines
7 Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of the
Philippines College of Medicine—Philippine General Hospital, University of the Philippines Manila,
Manila 1000, Philippines
8 Department of Otolaryngology—Head and Neck Surgery, University of the Philippines College of
Medicine—Philippine General Hospital, Manila 1000, Philippines
* Correspondence: smdepaz@up.edu.ph (S.L.M.d.P.-S.); lmdalmacio@up.edu.ph (L.M.M.D.)
Abstract: HPV infection is one of the most studied risk factors in cervical cancer—the second most
common cancer site and cause of death due to cancer in the Philippines. However, there is a lack of
population-based epidemiological data on cervical HPV infection in the Philippines. Local reports
on co-infections with other lower genital tract pathogens, commonly reported globally, are also
lacking, which emphasizes the need to increase efforts in targeting HPV prevalence, genotype, and
distribution. Hence, we aim to determine the molecular epidemiology and natural history of HPV
infection among reproductive-age Filipino women using a community-based prospective cohort
design. Women from rural and urban centers will be screened until the target sample size of 110
HPV-positive women (55 from rural sites and 55 from urban sites) is reached. Cervical and vaginal
swabs will be collected from all screened participants. For HPV-positive patients, HPV genotypes
will be determined. One hundred ten healthy controls will be selected from previously screened
volunteers. The cases and controls will comprise the multi-omics subset of participants and will be
followed up after 6 and 12 months for repeat HPV screening. Metagenomic and metabolomic anal-
yses of the vaginal swabs will also be performed at baseline, after 6 months, and after 12 months.
The results of this study will update the prevalence and genotypic distribution of cervical HPV
infection among Filipino women, determine whether the current vaccines used for HPV vaccination
programs capture the most prevalent high-risk HPV genotypes in the country, and identify vaginal
community state types and bacterial taxa associated with the natural history of cervical HPV infec-
tion. The results of this study will be used as the basis for developing a biomarker that can help
predict the risk of developing persistent cervical HPV infection in Filipino women.
Citation: de Paz-Silava, S.L.M.;
Tabios, I.K.B.; Tantengco, O.A.G.;
Climacosa, F.M.M.; Velayo, C.L.;
Lintao, R.C.V.; Cando, L.F.T.;
Perias, G.A.S.; Idolor, M.I.C.;
Francisco, A.G.; et al. Determinants
of Acquisition, Persistence, and
Clearance of Oncogenic Cervical
Human Papillomavirus Infection in
the Philippines Using a Multi-Omics
Approach: DEFEAT HPV Study
Protocol. Healthcare 2023, 11, 658.
https://doi.org/10.3390/
healthcare11050658
Academic Editor: Masafumi
Koshiyama
Received: 5 January 2023
Revised: 6 February 2023
Accepted: 13 February 2023
Published: 23 February 2023
Copyright: © 2023 by the authors. Li-
censee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and con-
ditions of the Creative Commons At-
tribution (CC BY) license (https://cre-
ativecommons.org/licenses/by/4.0/).
Healthcare 2023, 11, 658 2 of 15
Keywords: human papillomavirus; cervical cancer; epidemiology; vaccination; screening;
treatment; Philippines
1. Introduction
Cervical cancer is the second most common cancer site and the second most common
cause of death due to cancer in the Philippines and globally [1]. There were 570,000 cases
and 311,000 deaths worldwide from cervical cancer in 2018. More than 85% of these deaths
were found in low- and middle-income countries. First-world countries such as the United
States and China are also vulnerable to the high burden of HPV infection. As of 2021, the
reported number of annual cervical cancer cases in the United States was about 13,545,
while cervical cancer deaths amounted to 5706 cases [2]. Conversely, China had a higher
number of annual cases, with 109, 741 cervical cancer cases and 59,060 cervical cancer
deaths [3]. In the United States, the 5-year age-standardized relative survival rate for cer-
vical carcinoma is 64.2% [4]. On the other hand, according to the Centers for Disease Con-
trol and Prevention (CDC), the 5-year survival rates for cervical cancer are about 58% for
non-Hispanic Black women and 67% for non-Hispanic white women [5]. This is consistent
with the previous study and was rationalized to be due to the diagnosis of an earlier stage
of the disease.
Human papillomavirus infection is a necessary cause of cervical cancer [6] and is
considered the most common sexually transmitted infection worldwide [7]. In the Philip-
pines, cervical cancer is among the most common cancers, presenting an annual burden
of 7829 new cases and 4052 deaths [1]. The estimated national standardized mortality rate
for cervical cancer was 7.5 per 100,000. In total, 1 (0.7) out of 100 women would have died
from cervical cancer before age 75. The five-year relative survival rate for Filipinos is
45.4% [8].
Numerous epidemiological studies in several countries have confirmed that human
papillomavirus strongly correlates with cervical neoplasia. HPV DNA was detected in al-
most 93% of cervical cancer patients, with no significant variations in HPV positivity
among countries [9]. A study from 1991 to 1993 in the Philippines showed that HPV DNA
was present in 93.8% of patients diagnosed with squamous cell carcinoma and 90.9% of
patients with adenocarcinoma/adenosquamous carcinoma. Fifteen different HPV types
were detected in squamous cell carcinoma, while six HPV types were detected in adeno-
carcinoma/adenosquamous carcinoma [10].
One of the principal socioeconomic vulnerabilities cited for cervical cancer is poverty,
thus explaining the lack of effective screening programs to detect and treat precancerous
conditions and the inability to bear costs related to treatment, making cervical cancer in-
cidence much higher in developing countries [9]. This includes other factors, such as sys-
tem and practitioner delay, which are some healthcare-related challenges, and psycholog-
ical factors, such as negative social attitudes and distress associated with treatments
[11,12].
Human papillomavirus (HPV) infection is one of the most studied risk factors for
cervical cancer [13]. Although HPV is essential in the development of oncogenicity, as it
influences the conversion of cervical epithelial cells into their malignant counterparts,
other factors and molecular occurrences are needed for cervical cancer to develop [14].
About 200 different HPV groups have been characterized, with the majority having low
risk of developing cancer [15]. The individual viruses found within HPV groups are iden-
tified as high or low risk depending on their tendency to progress into malignant cells.
Low-risk HPV viruses (e.g., HPV-6 and HPV-11) only produce localized benign warts and
are non-malignant, while high-risk HPVs (e.g., HPV-16 and HPV-18) are linked to the de-
velopment of high-grade cervical lesions and invasive carcinoma [16,17].
Of all high-risk HPVs, HPV-16 is the most prominent strain identified and associated
with vaginal, vulval, anal, and penile cancers [18]. HPV-16 and HPV-18 are both known
Healthcare 2023, 11, 658 3 of 15
to be high-risk HPVs that have several functional coding regions that code for proteins
that control the function of E6 and E7 genes [18,19]. E6 genes are known to inhibit negative
regulators of the cell cycle and inhibit p53, a known transcription factor that activates
apoptosis [18,20]. On the other hand, E7 codes for viral proteins that bind to retinoblas-
toma tumor suppressor proteins. Therefore, despite the absence of normal mitogenic sig-
nals, the cells progress in the cell cycle. In the Philippines, HPV-18 is the most common
HPV type compared with other countries where HPV-16 is more prevalent [21].
Despite the risks, population-based epidemiological data on HPV in the general pop-
ulation in most parts of the Philippines remains unknown [22], which is emphasized by
the low HPV coverage in the country [23]. There is limited knowledge of HPV prevalence
and genotype distribution among healthy patients and those with cervical cancer. Based
on our current knowledge, only one study has been conducted to determine polymor-
phisms and genetic variants that influence the development of cervical cancer [23,24].
However, this emphasizes the need for further studies in the field.
Determining the HPV genotype and distribution among the general population can
help address the gap in the knowledge of the epidemiology of HPV in the Philippines
[23,25]. The molecular epidemiology of HPV genotype distribution is essential to estimate
the potential impact of prophylactic HPV vaccination and to assess the importance of HPV
testing-based cervical screening [26,27]. This study will update the prevalence and geno-
typic distribution of HPV infection among Filipino women of reproductive age, which can
determine whether available vaccines in the HPV vaccination program in the Philippines
capture the most prevalent high-risk HPV genotypes in the country. In addition, this
study will also identify vaginal community state types and bacterial taxa associated with
different infection statuses of HPV. This can be used in developing a biomarker that can
help predict the risk of developing persistent HPV infection and cervical cancer in Filipino
women.
Papanicolaou smear testing leads to the early detection and treatment of precancer-
ous cervical lesions in most developed countries with well-organized cytologic screening
programs [28–31]. This prevents the progression of cervical lesions to cervical cancer
[32,33]. However, in Asia, especially in developing countries, coverage of cervical cancer
screening programs is still low, mainly because of limited access, lack of knowledge about
the disease, and the absence of organized screening programs in some countries. These
contribute to the high burden of cervical cancer in most Asian countries, including the
Philippines [34].
Current screening strategies established in the country include pap smear testing and
visual inspection with acetic acid (VIA) [35], which is the current recommended method
by the Department of Health to be conducted at the population level, as it is more practical
than Pap smear tests [36–38]. Studies have shown that in the past five years, the current
screening coverage of HPV in the Philippines among women of reproductive age has been
2% [39], which is far from the 70% target coverage of the World Health Organization [40].
Numerous factors have been barriers to the current low-percent coverage of HPV screen-
ing programs in the country, including limited resources, geographic disparities, scarcity
of workforce and funding, high out-of-pocket costs for screening, and the lack of
knowledge of the importance of HPV screening programs [41]. There is a lack of popula-
tion-based screening for cancers in the Philippines, and little information is available to
quantify the delays in cancer interventions [42]. Most patients seek professional help in
hospitals for initial evaluation or during severe cases that are difficult to treat, but most
opt to look elsewhere for medical care, such as private medical service providers or tradi-
tional healers [43].
Multi-omics is a field of scientific research that integrates various omics data into one.
This approach combines two or more omics data sets that are then analyzed, visualized,
and interpreted to determine different biological processes based on a given scope [44].
Using a multi-omics approach, the study on HPV can be further integrated to guide future
researchers in the novel identification of potential targets and biomarkers in preventing
Healthcare 2023, 11, 658 4 of 15
the development of cervical cancers and the progression of persistent HPV infections
[45,46].
While it has already been established that HPV infection is a well-established risk
factor for cervical cancer, some factors may contribute to cervical carcinogenesis [47]. Vag-
inal dysbiosis has been a long-standing theory on the development of cervical cancer [48].
Studies have shown that cervical microflora differs significantly in HPV-positive and
HPV-negative women and in all stages of the natural history of cervical cancer [34,49,50].
Vaginal microbiomes were associated with the persistence and progression of high-risk
HPV infection in a prospective longitudinal cohort [51,52]. Recently, a meta-analysis that
included 15 prospective cohort studies showed a causal link between vaginal dysbiosis
and cervical cancer [53]. However, these studies have not been conducted in the Philip-
pines.
The present study protocol aims to determine the factors associated with the natural
history of cervical HPV infection in a cohort of women in rural and urban Philippines
centers using an omics approach. Specifically, it aims to (1) describe the sociodemographic
profile and reproductive health behavior of the study cohort; (2) determine the cervical
HPV infection prevalence and genotype distribution in the study cohort; (3) characterize
the vaginal microbiome and metabolomic profiles of HPV-positive and HPV-negative
study participants; and (4) identify factors influencing the acquisition, clearance, and per-
sistence of cervical HPV infection in the study cohort after 6 and 12 months at follow-up
examinations.
2. Materials and Methods
2.1. Study Design
The DEFEAT HPV Study or the Determinants oF Acquisition, persistence, and clear-
ance of oncogenic cervical Human Papillomavirus infection in a cohort of women in rural
and urban Philippines using a multi-OMICs approach, will employ a community-based
prospective cohort design. An initial cross-sectional study will identify age-matched
HPV-positive and HPV-negative individuals, who will be invited to participate in the lon-
gitudinal study (Figure 1).
Figure 1. Schematic diagram of participant enrollment during the study and data collection at each
time point in DEFEAT HPV study in the Philippines.
2.2. Sampling Design
The study will employ two non-probabilistic sampling techniques: convenience sam-
pling for the selection of study sites and quota sampling for the recruitment of study par-
ticipants. Patients will be recruited from the selected community centers and enrolled in
Healthcare 2023, 11, 658 5 of 15
the study if they satisfy the eligibility criteria. Recruitment and sample collection will con-
tinue until the desired number of participants is reached.
2.3. Sample Size
The sample size was based on Casals-Pascual et al., 2020, regarding the number of
participants required to find significant differences in alpha diversity in clinical microbi-
ome studies [54]. To find differences in microbial diversity between study groups with an
effect size of 0.55 and adequate power (80%), at least 110 HPV-positive participants must
be enrolled in the study. The most recent data from HPV and related cancers Fact sheet
2017 showed an HPV infection prevalence of 9.3% among women with normal cytology
[55]. Using an estimated prevalence of 9.3%, precision of 5%, and 10% adjustment for non-
participants, at least 1186 women (593 each in urban and rural centers) should be screened
during the initial survey to identify 110 HPV-positive patients (http://sampsize.source-
forge.net/iface/index.html) [56].
2.4. Study Sites
Recruitment of participants and subsequent sample collection will be performed in
Likhaan Center for Women’s Health clinic in Tondo, Manila (urban site), and Naic, Cavite
(rural site). These sites were selected based on good coordination between the principal
investigator and the non-government organization, and the availability of trained local
health personnel. Laboratory processing and molecular testing will be conducted at Vi-
rology Laboratory, Department of Medical Microbiology, College of Public Health, Uni-
versity of the Philippines Manila.
2.5. Study Population
2.5.1. Inclusion Criteria
The eligibility criteria for the initial cross-sectional survey will be the following:
women aged 21 years or older will be eligible to participate if they are currently sexually
active or seeking birth control and have an intact uterus. The eligibility criteria for the
longitudinal study will be the following: women aged 21 years or older included in the
initial cross-sectional survey who underwent HPV DNA PCR and Pap smear tests.
2.5.2. Exclusion Criteria
The exclusion criteria will be verified during the physician’s pelvic exam, by means
of medical record, and/or self-reported. Written informed consent will be obtained from
all participants. Exclusion criteria for the study will be current pregnancy; menstruating
during sample collection; taking antibiotics, antifungals, or antivirals currently or within
the previous three months; treatment for cervical intraepithelial neoplasia within the pre-
vious 18 months; having a current referral for hysterectomy or had a total or radical hys-
terectomy for any indication; use of douching substances, vaginal applied medications
and suppositories, feminine deodorant sprays, or vaginal lubricants within 48 h prior the
visit; any skin condition in the genital area interfering with the study; sexual intercourse
less than 48 h prior the visit; and having type I or type II diabetes, hepatitis, and HIV
infection.
Healthcare 2023, 11, 658 6 of 15
2.6. Study Procedure
2.6.1. Process for Securing Consent from the Participants
Informed consent will be given to target participants during the survey. They will be
given enough time to decide whether to participate in the study. The research team will
provide and discuss the research details, so they will be fully aware of the nature of the
study. Advantages and potential disadvantages will be discussed in full disclosure with
the participants. The research team will also provide the following information during the
process of securing consent: (1) significance of the study; (2) detailed flow on the processes
involved in the testing and validation of the samples they will submit; (3) disposal proto-
col of the samples they will submit; and (4) referral plan in case they will have abnormal
examination findings.
2.6.2. Referral Plan
Women receiving abnormal Pap smear results with positive PCR tests for oncogenic
HPV will be referred to the rural health unit of their respective municipalities for appro-
priate management. These participants will be given follow-up diagnostic recommenda-
tions that range from repeat Pap smears at 6 and 12 months to colposcopy (with or without
endocervical sampling) to loop electrosurgical excision.
2.6.3. Grouping of HPV Status at One-Year Follow-Up
To investigate the shifts in bacterial communities in the HPV states, we will group
the study participants based on the following conditions: (1) Group 1.1 (HPV negative)—
women who tested persistently negative in the detection of HPV types throughout 12
months (all negative during the observation period); (2) Group 1.2 (HPV acquisition)—
women who were HPV negative at baseline and then became HPV positive during the
follow-up period; (3) Group 2.1 (HPV clearance)—women who were HPV positive at
baseline and then became HPV negative during the follow-up period; (4) Group 2.2 (HPV
persistence)—women who were persistently HPV positive at baseline and during the fol-
low-up periods. Patients will be asked to follow up for the study two times, 6 and 12
months after the first visit.
2.7. Data Collection Tools
2.7.1. Clinical Interview and Examination
An interviewer-administered questionnaire will be used in this study. The data col-
lection tool will be pre-tested for content and face validity, and field interviewers will be
trained before field deployment. The following data will be collected: (1) sociodemo-
graphic characteristics (age, place of residence, educational attainment, monthly family
income, marital status, alcohol drinking, and smoking); (2) medical history (gravidity and
parity, age of menarche, number of lifetime sexual partners, history of sexually transmit-
ted infections, use of oral contraceptives, and previous Pap test or visual inspection with
acetic acid); (3) awareness and practices of cervical cancer preventive behavior; (4) sexual
and reproductive health behavior (use of contraceptives, number of children, age at first
oral intercourse, lifetime oral sexual partners, age at first vaginal intercourse, and lifetime
vaginal sexual partners). A licensed physician will conduct standard gynecological exam-
inations. These will be performed in a private room with the assistance of a nurse.
2.7.2. Sample Collection and Transport
A licensed physician will collect cervical and vaginal swabs. A sterilized speculum
will be inserted without lubricant. The cervical and vaginal swabs will be collected by
swabbing the cervix and the lateral walls of the mid vagina using an ENAT PM 2 mL L–
shape Applicator (Cat. No. 608CS01L; Seegene Inc., Seoul, South Korea) and an ENAT PM
2 mL Regular Applicator (Cat. No. 608CS01R; Seegene Inc.), respectively. The samples
Healthcare 2023, 11, 658 7 of 15
will then be immediately placed on ice and frozen at −80 °C within 1 h of collection. All
samples will be subjected to a Pap smear test. A licensed pathologist will conduct a cytol-
ogy report according to the Bethesda system. The cytology report will be categorized into
normal and abnormal. Routine cervical cytology will include negative for intraepithelial
lesion or malignancy (NILM) and inflammatory changes. Abnormal cervical cytology will
consist of atypical squamous cells of undetermined significance (ASC-US), low-grade
squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion
(HSIL), and squamous cell carcinoma (SCC). Urine and stool samples will be collected and
submitted for routine urinalysis and stool examination for the detection of parasitic infec-
tions. These tests will be performed by a licensed medical technologist and pathologist.
2.7.3. Genomic DNA Extraction
Genomic DNA will be extracted from cervical and vaginal swabs using the Qiagen
DNA Extraction Kit according to the manufacturer’s procedure. Extracted DNA in aque-
ous solution will be quantified (ratios of 260/280 and 260/230) using NanoDrop 2000 Spec-
trophotometer (Thermo Fisher Scientific, Wilmington, DE, USA). Sample adequacy will
be evaluated by means of the amplification of the human β-actin gene using 1 μL of ge-
nomic DNA, 6.25 μL of 2x QuantiTect® SYBR® Green, 0.625 μL of each 10 μM primer, and
4 μL of deionized distilled water, in a total volume of 12.5 μL. PCR will be conducted with
initial denaturation of 95 °C for 15 min, followed by 35 cycles of denaturation at 95 °C for
20 sec, annealing at 56 °C for 1 min, extension at 72 °C for 1 min, and final extension of 72
°C for 4 min. All samples that present positive for β-actin will be used for the detection of
HPV genotyping [57].
2.7.4. HPV Genotyping
The extracted genomic DNA from the cervical swabs will be subjected to HPV geno-
typing using Anyplex II HPV28 Detection Kit (Cat. No. HP7S00X; Seegene Inc.) following
the manufacturer’s instructions. This test can detect the HPV DNA of 28 anogenital HPV
types [58,59].
2.7.5. Detection of Lower Reproductive Tract Infections
The genomic DNA extracted from the vaginal swabs will be used to detect lower
genital tract infections (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma gen-
italium, Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum, and
Trichomonas vaginalis). AnyplexTM II STI-7 Detection (V1.1) (Cat. No.SD7700X, Seegene
Inc.) will be used following the manufacturer’s instructions. This kit is a cost-effective and
rapid diagnostic tool for detecting multiple sexually transmitted infections [60,61].
Bacterial vaginosis (BV) will be assessed using Amsel criteria [62] and the Nugent
score [63]. A licensed medical technologist and physician will process and assess the sam-
ples. At least three of the four Amsel criteria will be required for diagnosing BV using
Amsel criteria [64].
2.7.6. 16S Amplicon Metagenomic Sequencing Using 454 GS-FLX Plus
The protocol for metagenomic sequencing will be adapted from a previous study on
the association of the cervical microbial community and HPV infection status in Korean
women [50]. The raw sequences for the samples will be arranged using a unique barcode,
and low-quality reads (average quality score <25 or read length <300 bp) will be removed.
The primer sequences will be cut down by employing pairwise sequence alignment, and
sequences will be gathered to correct for sequencing errors. Taxonomic identification will
be performed using the EzTaxon-e public database according to the highest pairwise sim-
ilarity among the BLASTN search results. The UCHIME algorithm will remove possible
chimera sequences, and the diversity indices will be calculated in Mothur after normaliz-
ing the read number in each sample. The potential biomarkers linked to HPV negativity,
Healthcare 2023, 11, 658 8 of 15
HPV clearance, and HPV persistence will be analyzed using Liner discriminant analysis
(LDA) effect size (LEfSe). Finally, the effect relevance will be predicted using LDA.
2.7.7. Metabolite Extraction and Separation Using LC/MS
Briefly, cervicovaginal samples (50 μL) will be extracted using a 500 μL methanol.
The aqueous supernatant will be vacuum dried and reconstituted using water:acetonitrile
(4:1, v/v) solution [65]. A QC sample will be prepared by pooling aliquots of 1uL from each
sample. LC-MS will be conducted using a Vanquish UHPLC system in tandem with the
Orbitrap Fusion Tribrid with a heated electrospray ionization source. A gradient elution
using 0.1% FA in water (A) and 0.1% FA in acetonitrile (B) will be done using an Acclaim
C18 column. A full scan MS analysis via the Orbitrap detector will first be employed on
the QC sample. This will be injected after every five samples to serve as a reference. Data-
dependent acquisition using dynamic exclusion at a scan range of 80-1000 will be subse-
quently performed on the individual samples via collision-induced dissociation (CID)
with a linear ion trap detector.
The data will be analyzed using Compound Discoverer 3.2. The pre-set workflow
‘Untargeted Metabolomics with Statistics Detect Unknowns with Mapped Pathways and
ID using Online Database’ was used as a framework for the analysis with a few modifica-
tions to fit the sample study. The data will be pre-processed using the software’s own
algorithm, which includes retention time alignment and feature detection. Missing value
imputation using Random Forest will be used for dealing with missing values. Molecular
networks will be generated to create associations between spectra with high similarity.
Metabolika Pathways will be used to determine the significant biochemical pathways in-
volved. mzCloud search will be used as the main database for putative identification. Hits
with no mzCloud results will be putatively identified using ChemSpider database search.
2.8. Quality Control
Licensed physicians will perform all gynecological examinations with training on the
proper collection of cervical swabs for cytology. Two board-certified pathologists will in-
dependently examine the cytology samples. Data collectors and community health work-
ers who will help in sample collection and interviews will be oriented and trained at the
beginning of the study. English questionnaires will be translated into Filipino and back-
translated into English. A pre-test will be performed. Data will be encoded twice by two
individuals and then checked by a third person.
2.9. Statistical Analyses
Descriptive analysis using tables, frequency (%), and mean values will be used to
summarize and analyze the collected data. Descriptive analysis will be performed by ob-
taining quantitative variables’ means and standard deviations. Proportions and frequen-
cies will be reported for qualitative variables. The chi-square test will be used to test the
categorical variables, and the Kruskal–Wallis test will be employed to compare cohort
characteristics based on HPV infection status. One-way analysis of variance with Tukey’s
test will be used to assess differences in cohort characteristics based on the natural history
of HPV infection, i.e., acquisition, clearance, or persistence of the infection.
The multivariable logistic analysis will be performed after adjusting for age, meno-
pausal status, oral contraceptive use, and smoking habit. A logistic model with a robust
variance will be estimated to compare those with HPV persistence to those with HPV
clearance and HPV negativity. Hazard ratios (HRs) and 95% confidence intervals (CIs)
will be obtained from the models as measures of association. The statistical analyses will
be performed with SAS 9.4, and R version 3.3.1 with ggplot2 packages will be used for
visualization. The results will be considered statistically significant if p < 0.05.
Healthcare 2023, 11, 658 9 of 15
2.10. Ethical Consideration
This study was approved by the University of the Philippines Manila Research Ethics
Board (UPMREB 2021-0645-01) on 25 January 2022. Informed consent will be obtained
from the participants invited to participate in the study by one of the investigators or the
research assistant. The informed consent form will be in both English and Filipino. If the
patient is illiterate, the researcher/person taking consent will read out the informed con-
sent form in the presence of a literate witness. Participation in the study will be voluntary,
with the option to opt-out without reason and any penalty or issue. Assurance of privacy
and confidentiality and declaration of risks, benefits, compensation, and conflicts of inter-
est will be stated in the informed consent. The study will only proceed after the signing of
the certificate of informed consent in the said form by the participants. All procedures
performed in this study will follow the ethical standards of the institutional research com-
mittee and with the Helsinki Declaration and its later amendments.
3. Results
The primary outcomes of this study include the prevalence and genotype distribu-
tion of HPV infection among women in urban and rural communities in the Philippines.
This study will also document the persistence or clearance of HPV infection among HPV-
positive study participants and the incidence of HPV acquisition and negativity among
initially HPV-negative participants after 6 and 12 months. This study will also determine
the prevalence of reproductive tract infections (i.e., C. trachomatis, N. gonorrhoeae, M. geni-
talium, U. parvum., U. urealyticum, T. vaginalis, and bacterial vaginosis) among study par-
ticipants.
To further understand the risk factors associated with HPV infection in the Philip-
pines, the study will also determine the sexual and reproductive health behavior of par-
ticipants. Associations of sociodemographic factors and health behaviors and the status
of HPV infection will be obtained.
The vaginal microbiome and metabolomic profiles of patients will be obtained at the
time of enrollment, after 6 months, and after 12 months. Associations of vaginal microbi-
ome and metabolome and the status of HPV infection among study participants will be
performed. Distinct microbiome and metabolomic signatures can be used as potential bi-
omarkers for persistent HPV infection, a necessary cause of cervical cancer.
4. Discussion
Patients with cervical HPV infection do not commonly present symptoms. However,
some patients with persistent infection may manifest anogenital warts [14]. Persistent in-
fection with high-risk HPV may lead to the development of cervical cancer [23]. In the
Philippines, women are at high risk of contracting the infection and developing the dis-
ease. The country ranked last in the HPV vaccination program coverage compared with
other low–middle-income countries as of 2021 [66]. These data showed 23% and 5% pro-
gram HPV vaccination coverage rates in women for their first and second doses, respec-
tively [67].
Although cervical cancer is a preventable and manageable disease, various limita-
tions in the Philippines put Filipino women at high risk of contracting and dying from
HPV infection and cervical cancer. HPV vaccines were made available in 2006, in align-
ment with the thrusts of the World Health Organization (WHO) to immunize individuals
to prevent the development of HPV and cervical cancer [68]. Currently, a global agenda
is in place, as the WHO aims to eliminate HPV as a public health problem by 2030 through
the vaccination of at least 90% of 15-year-old females, the screening of 70% of women aged
35 years old through high-performance tests and a follow-up screening test by age 45, and
by providing management and treatment to preinvasive and invasive cervical cancer
cases in 90% of the women identified [68,69]. However, it was only in 2015 that HPV vac-
cination was incorporated into the National Immunization Program (NIP) [69] of the
Healthcare 2023, 11, 658 10 of 15
Philippine’s Department of Health, which was followed by HPV-specific school-based
vaccination in 2017 for school-age female children [70].
The lack of updated epidemiological information on HPV infection and cervical can-
cer in the country emphasizes the need for more research in this field. Despite recent ef-
forts, morbidity and mortality from HPV infection and cervical cancer remain high
[10,21,24]. Monitoring those at high risk of contracting HPV needs to be strengthened. The
current HPV vaccination program needs to be assessed and evaluated based on its impacts
on the current Filipino population [21,23]. The gains of the current project and its gaps
must be determined to create a far more strengthened and effective system. The epidemi-
ological data to be gathered in this study will provide evidence for strengthening health
policies and programs on HPV vaccination and cervical cancer screening in the Philip-
pines [21,42]. Data on the estimates of HPV infection and co-infections with other lower
genital infections among urban and rural reproductive-age Filipino women will be gen-
erated. Not only will this study generate data for translation and interpretation by local
health communities and fellow researchers, but the participants will also be given free
Pap tests and HPV screening during the study as part of the expected outcomes of this
research, particularly in its impact on and service to the community. The study reinforces
the importance of reproductive health and preventive care with a primary care approach
in the Philippines. Through the generated data, the study will provide insight into the
extent of the HPV disease burden in the Philippines. It will, therefore, guide decision-
makers in strategizing public health programs to control and eliminate HPV in the coun-
try. Moreover, the project results may have implications for the necessity of HPV vaccina-
tion among Filipino women of reproductive age.
The molecular assessment of the characteristics of HPV genotypes specific to the Phil-
ippines remains scarce. There is also limited information on the potential risk factors as-
sociated with persistent cervical HPV infection. It may require further validation to help
determine the predisposed susceptibility of Filipino women to infection and the possible
means of immunization that can be discovered [23]. Furthermore, assessing the various
HPV genotypes requires routine assessment to strengthen treatment modalities. Type-
specific HPV persistent infection may lead to failure in treatment due to the incomplete
elimination of HPV infection, cervical intraepithelial neoplasia (CIN), and the likelihood
of cervical cancer progression [23] This indicates the need for more frequent and con-
sistent surveillance and the identification of individuals infected with HPV. Moreover,
this study will also determine the vaginal microbiome, metabolome, and other sexually
transmitted infections associated with persistent cervical HPV infection. These data may
be used to develop diagnostic kits for persistent cervical HPV infection designed for the
Filipino population. Moreover, prognostic markers using the microbiome and metabo-
lome data may also be developed to help stratify patients at risk of having persistent cer-
vical HPV infection and cervical cancer.
Only about 50–60% of patients diagnosed with cervical cancer receive some form of
treatment [27], which emphasizes one of the difficulties faced by low–middle-income
countries in defeating HPV. Treatment proves difficult, with 23.7% of Filipinos living be-
low the poverty threshold [28] and 44.7% utilizing out-of-pocket expenses for healthcare
services [8,71]. The management of late-stage cervical cancer entails high treatment costs
in government hospitals. For every patient, multiple expensive imaging modalities (CT
scan, MRI, and ultrasound) are needed in addition to the prices of chemotherapy regimens
and surgical procedures. Hence, the disease burden also has implications on government
expenditures, such that screening, prevention, and early intervention in HPV infection
becomes imperative to decrease the economic burden of cervical cancer. This study will
provide insights into the local molecular epidemiology of HPV infection so that public
health strategies (e.g., prophylactic and screening measures, behavioral interventions, and
vaccination) can be guided to effectively decrease the prevalence of HPV infection and
HPV-associated cancers in the Philippines [26,72].
Healthcare 2023, 11, 658 11 of 15
Other projects are also in place in the country to intensify the fight against HPV and
cervical cancer, such as the Scale up Cervical Cancer Elimination with Secondary preven-
tion Strategy (SUCCESS) project, which has been recently launched by the Department of
Health in partnership with Jhpiego and funded by Unitaid on 12 April 2021 [73]. The pro-
ject shows potential, as it aims to provide enhanced and simplified screening tests for
HPV, capacity building, and preventive treatment through mass information dissemina-
tion. The DEFEAT HPV Project will complement the existing HPV and cervical cancer
prevention and testing in the country and expand coverage.
4.1. Limitations of the Study
Among the current limitations foreseen by the researchers in this project are its selec-
tion criteria, which include urban and rural areas in the Philippines. With this, the results
of the study may not be generalizable to the whole country and can only account for a
representative sample of the total population. Furthermore, the follow-up period of the
study is only limited to 12 months.
Regardless of the limitations, the DEFEAT HPV study provides a novel perspective
on assessing the prevalence of HPV among Filipino women at high risk of contracting
HPV and thereby developing cervical cancer. This presents an excellent opportunity not
only to improve HPV screening coverage in the country but also to upscale current efforts
toward reaching the 2030 target of the World Health Organization to accelerate the elim-
ination of cervical cancer as a public health problem (i.e., 70% of screening coverage; 90%
of HPV vaccination; and 90% of treatment in women with pre-cancer and 90% in women
with invasive cancer managed) [74].
5. Conclusions
In conclusion, the results of this study will be used to update the current prevalence
and genotypic distribution of cervical HPV infection in the reproductive-age Filipino
women population. With the use of a multi-omics approach, this study will improve our
understanding of the epidemiology of cervical HPV infection in the Philippines. This is
because multi-omics could provide researchers with a greater understanding of the flow
of information regarding HPV, as it assesses the original cause of the disease (genetic,
environmental, or developmental) to determine its functional consequences and interac-
tions during development. This study can provide new information that can be used to
guide public health programs and clinical practice guidelines on cervical HPV infection
in the Philippines.
Author Contributions: Conceptualization, S.L.M.d.P.-S., I.K.B.T., O.A.G.T., F.M.M.C., C.M.C., and
L.M.M.D.; methodology, S.L.M.d.P.-S., I.K.B.T., O.A.G.T., F.M.M.C., C.L.V., R.C.V.L., L.F.T.C.,
G.A.S.P., M.I.C.I., A.G.F., C.D.M.C., and L.M.M.D.; investigation, S.L.M.d.P.-S., I.K.B.T., O.A.G.T.,
C.L.V., M.I.C.I., A.G.F., and L.M.M.D.; data curation, O.A.G.T., A.G.F., F.M.M.C., C.L.V., R.C.V.L.,
L.F.T.C., G.A.S.P., M.I.C.I., and C.D.M.C.; writing—original draft preparation, O.A.G.T. and
C.D.M.C.; writing—review and editing, S.L.M.d.P.-S., I.K.B.T., O.A.G.T., and L.M.M.D.; supervi-
sion, S.L.M.d.P.-S., I.K.B.T., O.A.G.T., C.M.C., and L.M.M.D.; project administration, S.L.M.d.P.-S.,
I.K.B.T., O.A.G.T., F.M.M.C., C.L.V., and L.M.M.D.; funding acquisition, S.L.M.d.P.-S., I.K.B.T.,
O.A.G.T., F.M.M.C., C.L.V., R.C.V.L., L.F.T.C., G.A.S.P., M.I.C.I., C.M.C., and L.M.M.D. All authors
have read and agreed to the published version of the manuscript.
Funding: This study was funded by Department of Science and Technology—Philippine Council
for Health Research and Development.
Institutional Review Board Statement: The protocol for this research study will be submitted to
University of the Philippines Manila Research Ethics Board (UPMREB), and data collection will
begin after approval of the board.
Informed Consent Statement: Informed consent will be obtained from the participants invited to
take part in the study.
Data Availability Statement: Not applicable.
Healthcare 2023, 11, 658 12 of 15
Acknowledgments: The authors acknowledge the help of the research staff of this study: Andrea
Lois Benavides, Ma. Agnes Algarme, and Armand Cañeja. We also acknowledge the help of Likhaan
Center for Women’s Health for hosting this study in their clinics.
Conflicts of Interest: The investigators and the research team have no personal and/or financial
interests in this study.
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