Petra Zimmermann

Petra Zimmermann
Université de Fribourg · Department of Community Health

MD; PhD

About

82
Publications
13,522
Reads
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5,013
Citations
Citations since 2017
69 Research Items
4973 Citations
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Introduction
I am a clinical researcher in Paediatric Infectious Diseases with a special interest in the microbiome, especially the breast milk microbiome and its association with health outcomes
Additional affiliations
December 2015 - December 2017
The Royal Children's Hospital
Position
  • Fellow Pediatric Infectious Diseases
January 2014 - September 2015
Inselspital, Universitätsspital Bern
Position
  • Fellow Pediatric Infectious Diseases

Publications

Publications (82)
Article
Background: The incidence of nontuberculous mycobacterial (NTM) infections is increasing worldwide, particularly NTM lymphadenitis and skin infections (Buruli ulcer). This review summarizes the evidence for the protective effectiveness of BCG vaccination against NTM disease. Methods: A systematic search using PRISMA guidelines was done for contr...
Article
The immunomodulatory effects of probiotics may influence the response to vaccines. We systematically reviewed prospective randomised placebo-controlled studies in humans that have investigated the effect of probiotics on humoral vaccine responses. We found 26 studies, involving 3812 participants, investigating the effect of 40 different probiotic s...
Article
The intestinal microbiome plays a crucial role in the development of the immune system and regulation of immune responses. Many factors influence the composition of the infant intestinal microbiome and therefore the development and function of the immune system. This in turn may alter the risk of subsequent allergies, autoimmune diseases and other...
Article
Cervicofacial lymphadenitis is the most common manifestation of infection with non-tuberculous mycobacteria (NTM) in immunocompetent children. Although complete excision is considered standard management, the optimal treatment remains controversial. This study reviews the evidence for different management options for NTM lymphadenitis. A systematic...
Article
Monkeypox is a zoonotic disease, presenting with fever, lymphadenopathy and vesicular-pustular skin lesions, that historically has rarely been reported outside the endemic regions of Central and West Africa. It was previously thought that human-to-human transmission was too low to sustain spread. During 2022, the number of cases of monkeypox, cause...
Article
Background The intestinal microbiome provides a reservoir for antibiotic resistance genes (ARGs). The neonatal microbiome is more susceptible to disturbance from external factors than the established microbiome. Objectives In this review, we systematically summarise studies which investigated the intestinal resistome in neonates. Data sources MED...
Article
Full-text available
The intestine is the most densely colonized region of the body, inhabited by a diverse community of microbes. The functional significance of the intestinal microbiota is not yet fully understood, but it is known that the microbiota is implicated in numerous physiological processes of the host, such as metabolism, nutrition, the immune system, and r...
Article
Full-text available
Background: Coronavirus disease 2019 (COVID-19) can be more severe in infants compared to older children. To date, only few case series have reported data on neonates with COVID-19 including mostly asymptomatic neonates who were tested because of exposure to maternal SARS-CoV-2 infection. This study summarises epidemiological data, clinical charact...
Article
Full-text available
BACKGROUND: To date, few data are available about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in young children and the role of early-life childcare arrangements in transmission of the virus. In this study, we assessed the SARS-CoV-2 seroprevalence in children less than 6 years of age in the canton of Fribourg and id...
Article
Introduction: In 2020, a new disease entitled Pediatric Inflammatory Multisystem Syndrome temporally associated with COVID-19 (PIMS-TS), or Multisystem Inflammatory Syndrome in Children (MIS-C), emerged, with thousands of children affected globally. There is no available evidence based on randomized controlled trials (RCT) to date on the two most...
Article
Full-text available
The immunogenicity of vaccines in children with juvenile autoimmune rheumatic diseases (JARDs) can be reduced, there are additional safety concerns around vaccination, and there is a potential for worsening in disease activity. In this systematic review, we summarise studies that investigated the immunogenicity and safety of routine vaccines in chi...
Article
Full-text available
Coronavirus disease 2019 (COVID-19) is usually less severe in children compared to adults. This study describes detailed clinical characteristics, treatment and outcomes of children with COVID-19 in a non-hospitalised and hospitalised setting and quantifies factors associated with admission to hospital and intensive care unit in children with SARS-...
Article
Accurately determining the risk of long COVID is challenging. Existing studies in children and adolescents have considerable limitations and distinguishing long-term SARS-CoV-2 infection-associated symptoms from pandemic-related symptoms is difficult. Over half of individuals in this age group, irrespective of COVID-19, report physical and psycholo...
Article
Full-text available
Background: Antibiotics are among the most commonly used drugs in children. In addition to inducing antibiotic resistance, antibiotic exposure has been associated with long-term adverse health outcomes. Methods: A systematic search using PRISMA Guidelines to identify original studies reporting associations between antibiotic exposure and long-term...
Article
Although there are many hypotheses for the age-related difference in the severity of COVID-19, differences in innate, adaptive and heterolo-gous immunity, together with differences in endothelial and clotting function, are the most likely mechanisms underlying the marked age gradient. Children have a faster and stronger innate immune response to SA...
Article
Full-text available
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pregnancy is associated with a higher risk for severe morbidity and mortality when compared with infection in non-pregnant women of childbearing age. An increasing number of countries recommend immunization against SARS-CoV-2 in pregnant women. Recent studies provide prelimin...
Article
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BACKGROUND: When the periods of time during and after the first wave of the ongoing SARS-CoV-2/COVID-19 pandemic in Europe are compared, the associated COVID-19 mortality seems to have decreased substantially. Various factors could explain this trend, including changes in demographic characteristics of infected persons and the improvement of case m...
Article
Whether all children under 12 years of age should be vaccinated against COVID-19 remains an ongoing debate. The relatively low risk posed by acute COVID-19 in children, and uncertainty about the relative harms from vaccination and disease mean that the balance of risk and benefit of vaccination in this age group is more complex. One of the key argu...
Article
Full-text available
Background: The diagnosis of neonatal meningitis often rests on microscopic and biochemical findings in the cerebrospinal fluid (CSF). There is ongoing uncertainty about age-related normal values for CSF findings in neonates, and many previous studies have included infants in whom antibiotics were administered before lumbar puncture or in whom vir...
Article
In children, the risk of coronavirus disease (COVID) being severe is low. However, the risk of persistent symptoms following infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is uncertain in this age group, and the features of “long COVID” are poorly characterized. We reviewed the 14 studies to date that have reported per...
Article
Full-text available
In anticipation of an interseasonal respiratory syncytial virus (RSV) epidemic, a clinician-led reporting system was rapidly established to capture RSV infections in Swiss hospitals, starting in January 2021. Here, we present details of the reporting system and first results to June 2021. An unusual epidemiology was observed with an interseasonal s...
Article
Background Exploring factors that affect immune responses to immunizations in infants born to women immunized with tetanus-diphtheria-acellular-pertussis (Tdap) in pregnancy compared with unimmunized women is important in designing immunization programs. Methods Individual-participant data meta-analysis of 8 studies reporting post-immunization imm...
Article
Full-text available
Background: As clinical signs of COVID-19 differ widely among individuals, from mild to severe, the definition of risk groups has important consequences for recommendations to the public, control measures and patient management, and needs to be reviewed regularly. Aim: The aim of this study was to explore risk factors for in-hospital mortality a...
Article
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Background Immunization with tetanus-diphtheria-acellular pertussis (Tdap) vaccine in pregnancy is increasingly recommended. We determined the effect of Tdap immunization in pregnancy on infants’ vaccine responses. Methods Individual-participant data meta-analysis of ten studies (n=1884) investigating infants’ antibody response to routine immuniza...
Poster
Early diagnosis of osteomyelitis in children is critical to prevent long-term sequalae. However, not all bone lesions in children are osteomyelitis. We present an infant with decreased leg movements who was found to have multiple bone lesions and was diagnosed with sickle cell disease. Differentiation of vaso-occlusive ischemia/bone infarction fro...
Article
Full-text available
Background: Following the spread of the coronavirus disease 2019 (COVID-19) pandemic a new disease entity emerged, defined as Pediatric Inflammatory Multisystem Syndrome temporally associated with COVID-19 (PIMS-TS), or Multisystem Inflammatory Syndrome in Children (MIS-C). In the absence of trials, evidence for treatment remains scarce. Purpose: T...
Article
The neonatal period and early infancy are times of increased vulnerability to infection. The immune system of infants undergoes rapid changes and a number of factors can influence the maturation and function of the early infant immune system, amongst these factors are maternal infections and immunity. Infants who are HIV-exposed, but uninfected sho...
Article
Full-text available
Introduction The humoral response to vaccinations varies widely between individuals. There is no data available on the correlation between responses to different vaccines. In this study, we investigated the correlation of antibody responses between routine vaccine antigens in infants. Methods One and seven months after the 6-month vaccinations and...
Article
Full-text available
The kidneys and the urinary tract are a common source of infection in children of all ages, especially infants and young children. The main risk factors for sequelae after urinary tract infections (UTI) are congenital anomalies of the kidney and urinary tract (CAKUT) and bladder-bowel dysfunction. UTI should be considered in every child with fever...
Article
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The article “Swiss consensus recommendations on urinary tract infections in children”
Article
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Background: SARS-CoV-2/COVID-19, which emerged in China in late 2019, rapidly spread across the world with several million victims in 213 countries. Switzerland was severely hit by the virus, with 43,000 confirmed cases as of 1 September 2020. Aim: In cooperation with the Federal Office of Public Health, we set up a surveillance database in Febr...
Article
One of the main features of bacterial meningitis is pleocytosis. However, when children with meningitis present within hours of onset of symptoms, there is the possibility that the meninges are not yet sufficiently inflamed to lead to pleocytosis. A systematic search was done to identify published studies reporting children with culture- or polymer...
Preprint
Full-text available
Background SARS-CoV-2/COVID-19, which emerged in China in late 2019, rapidly spread across the world causing several million victims in 213 countries. Switzerland was severely hit by the virus, with 43’000 confirmed cases as of September 1st, 2020. Aim In cooperation with the Federal Office of Public Health, we set up a surveillance database in Fe...
Article
In contrast to other respiratory viruses, children have less severe symptoms when infected with the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this review, we discuss proposed hypotheses for the age-related difference in severity of coronavirus disease 2019 (COVID-19). Factors proposed to explain the difference in sever...
Article
Full-text available
We read with interest the review by Castagnoli et al summarizing case series of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 1065 children. The authors report the evidence up to March 3, 2020, and conclude that children with coronavirus disease 2019 (COVID-19) present mostly with mild symptoms, requiring supportive care...
Article
What time interval is needed between the administration of live attenuated vaccines to avoid interfering with the immune response to either vaccine? ►There is no evidence that live attenuated vaccines given within 28 days of each other diminish antibody responses, except for oral live attenuated vaccines (oral polio vaccine (OPV) and oral rotaviru...
Article
Full-text available
Introduction There is compositional overlap between the maternal intestinal microbiome, the breast milk microbiome and the infant oral and intestinal microbiome. Antibiotics cause profound changes in the microbiome. However, the effect of intrapartum and early-life antibiotics on the maternal intestinal and breast milk microbiome, and the infant or...
Article
Background To date, few data on paediatric COVID-19 have been published, and most reports originate from China. This study aimed to capture key data on children and adolescents with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection across Europe to inform physicians and health-care service planning during the ongoing pandemic....
Article
The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has spread rapidly across the globe. In contrast to initial reports, recent studies suggest that children are just as likely as adults to become infected with the virus but have fewer symptoms and less severe disease. In this review, we summarize the epidemiologic and c...
Article
Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E,-HKU1,-NL63 and-OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV)...
Article
Breastfeeding is associated with considerable health benefits for infants. Aside from essential nutrients, immune cells and bioactive components, breast milk also contains a diverse range of microbes, which are important for maintaining mammary and infant health. In this review, we summarise studies that have investigated the composition of the bre...
Article
Introduction: BCG vaccination reduces all-cause infant mortality in high-mortality settings by more than can be attributed to protection against tuberculosis. This is proposed to result from non-specific protection against non-vaccine targeted ('off-target') infections. There is also evidence that BCG protects against allergic diseases. Methods a...
Article
Objective: Antibiotics cause changes in the intestinal microbiota. The magnitude of the effect of antibiotics on the microbiota and whether the effects are only short-term or persist longterm remain uncertain. In this review, we summarise studies that have investigated the effect of antibiotics on the composition of the human intestinal microbiota....
Article
Introduction The use of intrapartum antibiotic prophylaxis (IAP) has become common practice in obstetric medicine and is used in up to 40% of deliveries. Despite its benefits, the risks associated with exposing large numbers of infants to antibiotics, especially long-term effects on health through changes in the microbiota, remain unclear. This sys...
Article
Aim: We investigated the effect of early-life factors, namely sex, delivery mode, feeding method and antibiotic exposure, on antibody responses to routine vaccinations administered during the first year of life. Methods: One and seven months after the primary course of routine vaccines and 1 month after routine vaccines at 12 months of age, anti...
Article
Full-text available
Introduction: Immunisation during pregnancy to protect infants against tetanus, pertussis and influenza is recommended in many countries. However, maternal antibodies can interfere with infant vaccine responses. We investigated the effect of antenatal diphtheria-tetanus-acellular pertussis (dTpa) and trivalent inactivated influenza (TIV) immunisati...
Poster
Background: A febrile child with mucocutaneous symptoms often represents a diagnostic challenge. Prompt evaluation of whether this common combination of symptoms is benign or corresponds to a more serious illness is crucial. Case Report: A previously healthy 5-year-old boy was admitted to our hospital after 7 days of fever, despite the intake of o...
Article
Introduction: Bacillus Calmette-Guérin vaccine (BCG), one of the most widely used vaccines, does not only provide protection against tuberculosis and other mycobacterial infections, but also has non-specific (heterologous) immunomodulatory effects. In participants in a randomised trial, we investigated the effect of neonatal BCG immunisation on ant...
Article
There is substantial variation between individuals in the immune response to vaccination. In this review, we provide an overview of the plethora of studies that have investigated factors that influence humoral and cellular vaccine responses in humans. These include intrinsic host factors (such as age, sex, genetics, and comorbidities), perinatal fa...
Article
Introduction Despite immunisation, antibiotics and intensive care management, infection with Streptococcus pneumoniae remains a major cause of morbidity and mortality in children. The WHO currently recommends vaccinating infants with either a 3+0 schedule (6 weeks, 3–4 and 4–6 months of age) or 2+1 schedule (2 doses before 6 months of age, plus a b...
Article
It is proposed that measles‐containing vaccines (MCV) have immunomodulatory effects which include a reduction in all‐cause childhood mortality. The antibody response to heterologous vaccines provides a means to explore these immunomodulatory effects. This is the first study to investigate the influence of measles‐mumps‐rubella (MMR) vaccine on the...
Article
Background Vaccines induce antigen-specific memory in adaptive immune cells that enable long-lived protection against the target pathogen. In addition to this, several vaccines have beneficial effects greater than protection against their target pathogen. These non-specific effects are proposed to be the result of vaccine-induced immunomodulation....
Article
Full-text available
Chronic nonbacterial osteomyelitis (CNO) and SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome are auto-inflammatory disorders manifesting as chronic inflammation of bones and joints, which in SAPHO is often accompanying by skin changes. The aetiology of these diseases is unknown, but includes genetic, infectious and immunolog...
Article
The intestinal microbiota plays an important role in development of the immune system and regulation of immune responses. This review summarizes the association between the intestinal microbiota and the development of allergic sensitization, eczema, and asthma in neonates and children. Overall, a greater relative abundance of Bacteroidaceae, Clostr...
Article
Introduction: Aspirin (acetylsalicylic acid, ASA) is a commonly used drug that is often co-administered during the treatment of infections. Salicylic acid (SAL), the active metabolite of ASA, has significant effects on bacteria that might improve or (more likely) compromise the effectiveness of antibiotics. Areas covered: In this review, we summar...
Article
Introduction: Bacillus Calmette-Guérin (BCG) vaccine is one of the most widely used vaccines worldwide. In addition to providing protection against tuberculosis, it has non-specific (heterologous) immunomodulatory effects. Areas covered: In our systematic review, we found eight studies, involving 2439 participants, investigating the influence of B...
Article
There is substantial variation between individuals in the immune response to vaccinations. The intestinal microbiome plays a crucial rule in the development and regulation of the immune system and therefore its composition might affect how individuals respond to vaccinations. In this review, we summarise studies that investigated the influence of t...
Poster
Neurological complications due to VZV reactivation can develop in immunocompetent children and adolescents. Rare complications of lumbosacral herpes zoster include neurogenic bladder dysfunction, ileus with intestinal obstruction or transverse myelitis with possible persistent paralysis or sensory deficits. Hence, despite of poor quality evidence i...
Article
Full-text available
Background: The mechanisms underlying the non-antimicrobial immunomodulatory properties of macrolides are not well understood. Objectives: To systematically review the evidence for the immunomodulatory properties of macrolides in humans and to describe the underlying mechanism and extent of their influence on the innate and adaptive immune system....
Article
Group B streptococcus (GBS) is one of the most common causes of neonatal sepsis and meningitis. Intra-partum antibiotic prophylaxis does not play a significant role in reducing the risk of GBS late-onset disease. One of the proposed mechanisms for GBS late-onset disease is infection through contaminated breast milk. Infants in whom breast milk is t...
Article
Recent studies suggest that the incidence of nontuberculous mycobacterial infections in children may be increasing. Nontuberculous mycobacterial lymphadenitis, skin and soft tissue infection, and pulmonary disease each present unique challenges in relation to diagnosis and treatment. In this update, we critically review the recent literature on the...
Article
Antipyretics are some of the most commonly used drugs. Since they are often co-administered with antimicrobial therapy, it is important to understand the interactions between these two classes of drugs. Our review is the first to summarise the antimicrobial effects of antipyretic drugs and the underlying mechanisms involved. Antipyretic drugs can i...
Article
We present an infant with brachial plexus palsy who had osteomyelitis of the humerus, and summarize previously reported cases. Although Staphylococcus aureus is the most common pathogen in osteomyelitis in infants, group B streptococcus is responsible for 40% of humeral osteomyelitis. Early diagnosis is critical to prevent long-term sequalae, but i...
Article
Full-text available
Background A cephalhaematoma is usually a benign condition which resolves spontaneously. Nevertheless, there is a small risk of primary or secondary infection and diagnosis of this condition is challenging. The purpose of this article is to summarise risk factors, clinical criteria, pathogenesis, appropriate investigations and treatment methods for...
Article
SAPHO syndrome manifests as chronic inflammation of bones and joints, which may or may not be accompanied by skin changes. The term SAPHO is an acronym that stands for synovitis, acne, pustulosis (usually palmoplantar), hyperostosis and osteitis. The bones most commonly affected are those in the anterior chest wall (mainly the sternum, clavicles an...
Article
Odontoid osteomyelitis (OOM) is frequently misdiagnosed as torticollis, leading to a delay in diagnosis. We present two illustrative cases and a systematic literature review summarizing previously reported cases. OOM should be considered in children presenting with decreased head-movements and elevated ESR, particularly without improvement while re...
Poster
Odontoid osteomyelitis (OOM) is frequently misdiagnosed as torticollis, leading to a delay in diagnosis. We present two illustrative cases. OOM should be considered in children presenting with decreased head-movements and elevated ESR, particularly without improvement while receiving anti-inflammatory treatment. Plain radiographs can be misleading...
Article
Full-text available
International travel continues to increase in frequency. Health care providers need a wide understanding of the spectrum of travel related diseases and their management. This retrospective study analyses the demographic and clinical data of 360 travellers returning from the tropics presenting to an outpatient clinic at a tertiary hospital between 2...
Poster
Cervicofacial lymphadenitis is the most common manifestation of infection with non-tuberculous mycobacteria (NTM) in immunocompetent children. Although complete excision is considered standard management, the optimal treatment remains controversial. We reviewed the evidence for different management options for NTM lymphadenitis.
Poster
Diagnosis of infection in a cephalhaematoma is not easy. Elevated inflammatory markers do not necessary mean that there is an infection. We outline risk factors, clinical criteria and appropriate methods for investigating cephalhaematomas for possible infection.
Poster
he charts of 360 patients returning from a developing country were reviewed. The spectrum and frequency of different symptoms and diseases were correlated to the areas visited. We analysed the duration and purpose of travel to delineate their effect on clinical presentation. The diagnostic strategies and the applied therapies were investigated.
Article
Full-text available
Actinobaculum schaalii was first described as a causative agent for human infection in 1997. Since then it has mainly been reported causing urinary tract infections (UTI) in elderly individuals with underlying urological diseases. Isolation and identification is challenging and often needs molecular techniques. A. schaalii is increasingly reported...
Article
An 11-year-old girl presented with sudden sensory disturbance and left-sided muscle weakness. MRI revealed ischaemic change in the right lateral thalamus and the right internal capsule. During sonographic work-up of the cervical arteries, inflammation of the thyroid gland was noted. The results of the thyroid function tests and antibody titers conf...

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Project (1)
Project
In this prospective cohort study, we will determine the effect of (i) intrapartum antibiotics on the composition of the breast milk, and the infant oral and intestinal microbiota and antibiotic exposure in the first year of life on the composition of the infant intestinal microbiota (including the development and persistence of antibiotic resistance) and (ii) the association of this disruption with adverse health outcomes. (iii) We will also determine the association between the maternal intestinal microbiota, the breast milk microbiota and the infant oral and intestinal microbiota.