[Show abstract][Hide abstract] ABSTRACT: Objective:
The goal of this study was to determine if congenital human herpesvirus-6 (HHV-6) infection influences early neurodevelopment.
We enrolled 57 newborns with HHV-6 congenital infection and 242 control newborns without congenital infection into a prospective, double-blind study with 4 visits between 4 and 30 months of age. Assessments included the Fagan Test of Infant Intelligence, the Visual Expectation Paradigm, and the Mental Development Index (MDI) of the Bayley Scales of Infant Development II. Newborn audiology screening and follow-up audiology examinations were completed at 12 to 24 months.
No differences were noted in baseline characteristics between infants with HHV-6 congenital infection and control infants. No clinical syndrome due to congenital infection with HHV-6 was evident at birth. No differences were identified on the Fagan Test of Infant Intelligence or the Visual Expectation Paradigm between the two groups. In 39 infants with HHV-6 congenital infection, the mean ± SD Bayley Scale of Infant Development II MDI score was 103.4 ± 8.9 at 12 months of age. The matched control infants had a mean score of 105.4 ± 12.4. After controlling for covariates, HHV-6 congenital infection was associated with lower scores on the Bayley Scale of Infant Development II MDI at 12 months of age (mean difference: 4.3 [95% confidence interval: 0.4 to 8.1]; P = .03) compared with infants without HHV-6 congenital infection.
Congenital HHV-6 infection may have a detrimental effect on neurodevelopment at 12 months of age and requires further study given that congenital infection with HHV-6 is present in ∼1 in every 101 births.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Multipathogen reverse transcription real-time PCR (RT-qPCR) platforms have proven useful in surveillance for acute respiratory illness (ARI) and study of respiratory outbreaks of unknown etiology. The TaqMan(®) Array Card (TAC, Life Technologies™), can simultaneously test 7 clinical specimens for up to 21 individual pathogens (depending on arrangement of controls and use of duplicate wells) by arrayed singleplex RT-qPCR on a single assay card, using minimal amounts of clinical specimens. A previous study described the development of TAC for the detection of respiratory viral and bacterial pathogens; the assay was evaluated against well-characterized analytical materials and a limited collection of human clinical specimens. OBJECTIVES: We wished to compare TAC assay performance against standard individual RT-qPCR assays for respiratory viral detection, focusing on 10 viruses (adenovirus, human metapneumovirus, human parainfluenza viruses 1-4, influenza viruses A and B, respiratory syncytial virus, and rhinovirus) from a larger collection of human specimens. STUDY DESIGN: We used specimens from 942 children with ARI enrolled systematically in a population-based, ARI surveillance study (New Vaccine Surveillance Network, NVSN). RESULTS: Compared with standard individual RT-qPCR assays, the sensitivity of TAC for the targeted viruses ranged from 54% to 95% (54%, 56%, and 75% for adenovirus, human parainfluenza viruses-1 and -2, respectively, and 82%-95% for the other viruses). Assay specificity was 99%, and coefficients of variation for virus controls ranged from 1.5% to 4.5%. CONCLUSION: The TAC assay should prove useful for multipathogen studies and rapid outbreak response.
No preview · Article · Apr 2013 · Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology
[Show abstract][Hide abstract] ABSTRACT: Influenza vaccine immunogenicity in premature infants is incompletely characterized.
To assess the immunogenicity of trivalent, inactivated influenza vaccine (TIV) in extremely low-birth-weight (≤ 1000 g birth weight) premature (<30 weeks gestation) infants. We hypothesized that geometric mean titers of influenza antibody would be lower in premature than in full-term (FT) (≥ 37 week) infants.
In this prospective multicenter study, former premature and FT infants who were 6 to 17 months of age received 2 doses of TIV during the 2006-2007 or 2007-2008 influenza seasons. Sera were drawn before dose 1, and 4 to 6 weeks after dose 2. Antibody was measured by hemagglutination inhibition.
Over 2 years, 41 premature and 42 FT infants were enrolled; 36 and 33 of these infants, respectively, had postvaccination titers available. Premature infants weighed less (mean, 1.3-1.8 kg difference) at the time of immunization than FT infants. Prevaccination titers did not differ between groups. Premature infants had higher postvaccination antibody geometric mean titers than FT infants to H1 (2006-2007, 1:513 vs. 1:91, P = 0.03; 2007-2008, 1:363 vs. 1:189, P = 0.02) and B/Victoria (2006-2007, 1:51 vs. 1:10, P = 0.02). More premature than FT infants had antibody titers ≥ 1:32 to B/Victoria (85% vs. 60%, P = 0.04) in 2007-2008. Two (5%) premature and 8 (19%) FT infants had adverse events, primarily fever, within 72 hours after vaccination. No child had medically diagnosed influenza.
Former premature infants had antibody responses to 2 TIV doses higher than or equal to those of FT children. Two TIV doses are immunogenic and well tolerated in extremely low-birth-weight, premature infants 6 to 17 months old.
[Show abstract][Hide abstract] ABSTRACT: Human herpesvirus 6 (HHV-6) causes ubiquitous infection in early childhood with lifelong latency or persistence. Reactivation of HHV-6 has been associated with multiple diseases including encephalitis. Chromosomal integration of HHV-6 also occurs. Previous studies have suggested that the detection of HHV-6 DNA in plasma is an accurate marker of active viral replication.
We sought to determine whether PCR assays on plasma could correctly differentiate between primary HHV-6 infection, chromosomal integration of HHV-6 and latent HHV-6 infection.
We performed qualitative PCR, real-time quantitative PCR (RQ-PCR), and reverse-transcriptase PCR (RT-PCR) assays on samples of peripheral and cord blood mononuclear cells, as well as plasma, from groups of subjects with well defined HHV-6 infection, including subjects with chromosomally integrated HHV-6.
The detection of HHV-6 DNA in plasma was 92% sensitive compared to viral isolation for the identification of primary infection with HHV-6. All plasma samples from infants with chromosomally integrated HHV-6 had HHV-6 DNA detectable in plasma while only 5.6% were positive by RT-PCR. The specificity of plasma PCR for active replication of HHV-6 was 84% compared to viral culture while the specificity of RT-PCR was 98%. Our results demonstrate that qualitative or quantitative PCR of plasma is insufficient to distinguish between active viral replication and chromosomal integration with HHV-6. We found a higher specificity of RT-PCR performed on PBMC samples compared to PCR or RQ-PCR performed on plasma when evaluating samples for active HHV-6 replication.
Full-text · Article · Mar 2010 · Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology
[Show abstract][Hide abstract] ABSTRACT: Congenital human herpesvirus 6 (HHV-6) infection results from germline passage of chromosomally integrated HHV-6 (CI-HHV-6)
and from transplacental passage of maternal HHV-6 infection. We aimed to determine whether CI-HHV-6 could replicate and cause
transplacentally acquired HHV-6 infection. HHV-6 DNA, variant type, and viral loads were determined with samples (cord blood,
peripheral blood, saliva, urine, and hair) obtained from 6 infants with transplacentally acquired HHV-6 and with samples of
their parents' hair. No fathers but all mothers of infants with transplacentally acquired HHV-6 had CI-HHV-6, and the mother's
CI-HHV-6 variant was the same variant causing the transplacentally acquired congenital HHV-6 infection. This suggests the
possibility that CI-HHV-6 replicates and may cause most, if not all, congenital HHV-6 infections.
Preview · Article · Feb 2010 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: We examined the frequency and characteristics of chromosomally integrated human herpesvirus 6 among congenitally infected children.
Infants with and without congenital human herpesvirus 6 infection were prospectively monitored. Cord blood mononuclear cell, peripheral blood mononuclear cell, saliva, urine, and hair follicle samples were examined for human herpesvirus 6 DNA. Human herpesvirus 6 RNA, serum antibody, and chromosomally integrated human herpesvirus 6 levels were also assessed.
Among 85 infants, 43 had congenital infections and 42 had postnatal infections. Most congenital infections (86%) resulted from chromosomally integrated human herpesvirus 6; 6 infants (14%) had transplacental infections. Children with chromosomally integrated human herpesvirus 6 had high viral loads in all sites (mean: 5-6 log(10) genomic copies per mug of cellular DNA); among children with transplacental infection or postnatal infection, human herpesvirus 6 DNA was absent in hair samples and inconsistent in other samples, and viral loads were significantly lower. One parent of each child with chromosomally integrated human herpesvirus 6 who had parental hair samples tested had hair containing human herpesvirus 6 DNA. Variant A caused 32% of chromosomally integrated human herpesvirus 6 infections, compared with 2% of postnatal infections. Replicating human herpesvirus 6 was detected only among chromosomally integrated human herpesvirus 6 samples (8% of cord blood mononuclear cells and peripheral blood mononuclear cells). Cord blood human herpesvirus 6 antibody levels were similar among children with chromosomally integrated human herpesvirus 6, transplacental infection, and postnatal infection and between children with maternal and paternal chromosomally integrated human herpesvirus 6 transmission.
Human herpesvirus 6 congenital infection results primarily from chromosomally integrated virus which is passed through the germ-line. Infants with chromosomally integrated human herpesvirus 6 had high viral loads in all specimens, produced human herpesvirus 6 antibody, and mRNA. The clinical relevance needs study as 1 of 116 newborns may have chromosomally integrated human herpesvirus 6 blood specimens.
[Show abstract][Hide abstract] ABSTRACT: Although both human herpesvirus (HHV) 6 and HHV-7 infections are ubiquitous during childhood, few acute HHV-7 infections are
identified. It is unknown whether HHV-7 viremia indicates primary infection, as with HHV-6, or reactivation, and if these
differ clinically. We studied, in otherwise healthy children ⩽10 years old, HHV-7 and HHV-6 infections and their interaction
by serologic assessment, viral isolation, and polymerase chain reaction. In children ⩽24 months of age, HHV-7 infections occurred
less often than HHV-6 infections (P⩽.002). Of 2806 samples from 2365 children ⩽10 years old, 30 (1%) showed evidence of HHV-7
viremia; 23 (77%) of these were primary and 7 (23%) were reactivated HHV-7 infections. Four (13%) showed concurrent HHV-6
viremia, 2 associated with primary HHV-7 infections. The clinical manifestations of primary and reactivated HHV-7 infections
were similar, except that seizures occurred more frequently in reactivated infections. These findings, previously unrecognized
in otherwise healthy children, suggest that HHV-7 viremia could represent primary or reactivated infection and may be affected
by the interaction between HHV-6 and HHV-7
Preview · Article · Apr 2006 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: To determine in healthy children after primary infection the persistence of human herpesvirus 6 (HHV6) DNA, the presence and frequency of HHV6 re-activation or re-infection, and the relationship of both to illness and the presence of human herpesvirus 7 (HHV7) infection.
Children 1 to 12 years of age with previous HHV6 infection were prospectively evaluated by HHV6 and HHV7 DNA polymerase chain reaction (PCR) and reverse transcription (RT)-PCR for HHV6. HHV6 plasma antibody titers were measured. Illnesses were recorded by diary, and physician records were reviewed.
HHV6 DNA was detected in >or=1 peripheral blood mononuclear cell (PBMC) samples in 89% of children. HHV6 reactivation and re-infection were detected by RT-PCR in 1.1% of samples. Detection of HHV6 DNA was intermittent in 76% of children and was not associated with cumulative rates of illness. Illness at a study visit was significantly associated with the absence of HHV6 and HHV7 DNA in PBMC samples and was not associated with HHV6 antibody titer or the presence of HHV6 DNA in saliva.
HHV6 DNA persists in most children intermittently following primary infection and is unrelated to illness. Reactivation of HHV6 occurs in healthy children without apparent illness.
No preview · Article · Nov 2004 · Journal of Pediatrics
[Show abstract][Hide abstract] ABSTRACT: To examine whether: (1) congenital human herpesvirus 6 (HHV6) and human herpesvirus 7 (HHV7) infections occur; whether (2) their manifestations differ from postnatal infections; and whether (3) HHV6 and HHV7 infections differ despite their close relatedness.
HHV6 and HHV7 infections acquired congenitally and postnatally in normal children were compared using viral isolation, serology, reverse-transcription polymerase chain reaction (RT-PCR) and nested DNA-PCR for HHV6 variant A (HHV6A), HHV6 variant B (HHV6B), and HHV7.
HHV6 DNA was detected in 57 (1%) of 5638 cord bloods. HHV7 DNA, however, was not detected in 2129 cord bloods. Congenital HHV6 infections differed from postnatal infections, which were acute febrile illnesses. Congenital infections were asymptomatic, 10% demonstrated reactivation at birth, and HHV6 DNA persistence in follow-up blood samples was significantly more frequent. One-third of congenital infections were HHV6A, whereas all postnatal infections were HHV6B.
Congenital HHV6 infections occurred in 1% of births, similar to the rate for cytomegalovirus infection. Congenital infections were clinically and virologically distinct from postnatal infections. Congenital HHV7 infections, however, were not detected, suggesting considerable differences in transmission and pathogenesis in these closely related beta-herpesviruses.
No preview · Article · Nov 2004 · Journal of Pediatrics
[Show abstract][Hide abstract] ABSTRACT: During 1975–1995, a total of 2960 healthy adults, 18-60 years of age, were prospectively evaluated for respiratory virus infections.
Of these subjects, 211 (7%) acquired respiratory syncytial virus (RSV) infection. The infections were symptomatic in 84% of
subjects, involved only the upper respiratory tract in 74%, and included lower respiratory tract symptoms in 26%. Overall,
40% of the subjects were febrile. Lower respiratory tract signs developed in 26%. RSV illnesses were more prolonged than non-RSV
respiratory illnesses.Compared with influenza, RSV infections were less frequently associated with fever and headache, but
were associated significantly more often with nasal congestion, ear and sinus involvement, and productive cough. Absence from
work during the acute phase of the illness resulted from 38% of RSV infections and 66% of influenza cases. The mean duration
of RSV illness (9.5 days), however, was significantly longer than that of influenza (6.8 days). The occurrence of annual epidemics
of RSV, the virus' potential to reinfect all age groups, and the morbidity associated with these reinfections suggest that
RSV infections in working adults may result in appreciable costs for medical visits and absence from work.
Preview · Article · Oct 2001 · Clinical Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: The role of human herpesvirus 6 (HHV-6) in disease beyond primary infection remains unclear. We have developed and validated a new reverse transcription-PCR (RT-PCR) assay for HHV-6 that can determine the presence of HHV-6 in clinical specimens and differentiate between latent and replicating virus. Peripheral blood mononuclear cells from 109 children were evaluated for HHV-6 by RT-PCR, DNA PCR, and viral culture. Of these samples, 106 were suitable for analysis. A total of 20 samples were positive for HHV-6 by culture and DNA PCR, of which 19 were positive by RT-PCR (sensitivity, 95%). All 28 samples from children that were negative by viral culture, but positive by DNA PCR, were negative for viral transcripts by our RT-PCR assay. One positive RT-PCR result was observed in 56 samples that were negative by tissue culture and DNA PCR. This indicates a low rate of false-positive results (1.2%) and a specificity of 98.8%. This RT-PCR assay can reliably differentiate between latent and actively replicating HHV-6 and should allow insight into the pathogenesis of this ubiquitous virus.
Preview · Article · Dec 1999 · Journal of Clinical Microbiology
[Show abstract][Hide abstract] ABSTRACT: Human respiratory syncytial virus (HRSV) is classified into two major groups, A and B, each of which contains multiple variants. To characterize the molecular epidemiology of HRSV strains over time, sequencing studies of a variable region of the attachment protein gene from a single community in the United States during 5 successive years were performed. Phylogenetic analysis revealed distinct clades (genotypes) that were further classified in subtypes based on > or = 96% nucleotide similarity. Five genotypes and 22 subtypes among 123 group A HRSV isolates, and four distinct genotypes and six subtypes among 81 group B HRSV isolates were identified. One to two genotypes or subtypes accounted for > or = 50% of isolates from a given year. A shift in the predominant genotype or subtype occurred each year such that no genotype or subtype predominated for more than 1 of the 5 study years. The consistency in the displacement of the predominant strain suggests that a shift, even within the same group, is advantageous to the virus. It was hypothesized that the 'novel' strain is better able to evade previously induced immunity in the population and consequently either circulates more efficiently or is more pathogenic. The yearly shift in HRSV strains may contribute to the ability of HRSV to consistently cause yearly outbreaks of HRSV disease. These results also suggest that isolates may need to be characterized as to both group and genotype to fully understand protective immunity after natural infection and efficacy studies of candidate vaccines.
Preview · Article · Oct 1998 · Journal of General Virology
[Show abstract][Hide abstract] ABSTRACT: To define the clinical and virologic characteristics of primary human herpesvirus 7 (HHV-7) infection and to compare these characteristics with those of primary human herpesvirus 6 (HHV-6) infection.
A prospective convenience sample study of 496 children < or =3 years old. HHV-7 and HHV-6 infections were identified by viral isolation. Polymerase chain reaction and serology for HHV-7 and HHV-6 were performed. Clinical and laboratory characteristics of patients were obtained from medical records and follow-up interviews.
Children with primary HHV-7 infection (n = 8) were identified and compared with children with primary HHV-6 infection (n = 29) detected during the same time period. All children were febrile (mean temperature 39.8 degrees C) with no difference in the degree of fever, frequency of rash, or gastrointestinal complications between the groups. The median age of children with primary HHV-7 infection was 26 months, significantly older than that of children with primary HHV-6 infection (median, 9 months). Children with primary HHV-7 infection were also more likely than those with primary HHV-6 infection to have seizures associated with the illness (P = .004).
Primary infection with HHV-7 can cause a highly febrile illness in childhood, complicated by seizures. The serologic diagnosis of primary HHV-6 and HHV-7 infections may be confounded by cross-reacting antibodies.
No preview · Article · Oct 1998 · Journal of Pediatrics
[Show abstract][Hide abstract] ABSTRACT: Little is known of the persistence and pathogenicity of human herpesvirus 6 (HHV-6) after primary infection, including the role of strain variant. Over 2 to 5 years, 2,716 children and 149 families were studied. Peripheral blood mononuclear cell (PBMC), saliva, and cerebrospinal fluid (CSF) specimens were examined for HHV-6 DNA and variant. Ninety-nine percent of isolates causing primary infection were HHV-6 variant B (HHV-6B), which predominated in 95%-98% of the variants persisting in PBMC and saliva specimens from children and adults. Of 668 CSF samples, 13% contained HHV-6 DNA; of 77 children examined after primary infection, 61% had HHV-6 DNA detected only in their CSF and 39% had HHV-6 DNA in both CSF and PBMCs. HHV-6 variant A (HHV-6A) was detected significantly (P = .0001) more frequently in CSF than in PBMCs or saliva. In children for whom HHV-6 was identified in both CSF and PBMCs, PBMCs contained only HHV-6B, while CSF contained HHV-6A or HHV-6B, not both. Thus, in patients with dual infection, only HHV-6A persisted in CSF, which suggests that HHV-6A has greater neurotropism. Findings for adults indicate that dual infection occurs; variant persistence is similar to that for children. The frequency of HHV-6A infection increased little with age, thereby indicating that HHV-6A infection remains uncommon into adulthood. This study suggests that HHV-6 variants have different immunobiologic courses and neurotropism.
Preview · Article · Feb 1998 · Clinical Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: To test the hypothesis that children experiencing first febrile seizures caused by human herpesvirus 6 (HHV-6) have an increased risk for recurrent seizures when compared with children experiencing first febrile seizures attributed to other illnesses.
Descriptive prospective study of 36 HHV-6 culture-positive children and a matched subgroup of 86 HHV-6 culture-negative children, all of whom had their first febrile seizures evaluated in a tertiary care emergency department and were followed for at least 12 months, with an average follow-up of 35.7 months.
The recurrence of seizures among HHV-6 culture-positive and HHV-6 culture-negative children with no known previous neurologic deficits.
A decreased incidence of recurrent seizures occurred in children whose first febrile seizures were caused by HHV-6. Twenty percent of HHV-6 culture-positive children and 40% of HHV-6 culture-negative children (P < 0.038) experienced a recurrent seizure within 1 year of their first febrile seizure. The mean time to recurrence within 12 months was 8.6 months for children with HHV-6 infection and 3.8 months (P < 0.001) for children without HHV-6 infection. Most recurrent seizures occurred within 12 months of a first febrile seizure for both HHV-6-positive and HHV-6-negative children (88 and 91%).
Children who had their first febrile seizures caused by primary HHV-6 infection did not demonstrate an increased risk for recurrent seizures when compared with children whose first febrile seizures were from other etiologies.
No preview · Article · Jan 1998 · The Pediatric Infectious Disease Journal
[Show abstract][Hide abstract] ABSTRACT: The results obtained with an enzyme-linked immunosorbent assay (ELISA) for detection of human herpesvirus 6 (HHV-6) immunoglobulin G using a single 1:100 dilution of serum correlated well with those found by an indirect fluorescence microscopic assay (IFA) (r = 0.71). Concordant results were found in all 7 paired serum samples obtained from patients with acute primary infections and in 37 of 41 (90.24%) single serum samples. Fourteen serum samples (25%) which yielded nonspecific results by IFA were evaluable by ELISA. In a serologic survey using the ELISA, a disproportionate number of 12-month-old infants had low difference-of-optical-density values, suggesting that maternal antibody might persist beyond a year of age. This finding and the rises in antibody to HHV-6 found in patients with primary cytomegalovirus infections might lead to overestimation of HHV-6 infection rates in young children in seroprevalence studies. Other herpesvirus infections produced lesser effects on anti-HHV-6.
Preview · Article · Dec 1997 · Clinical and Diagnostic Laboratory Immunology
[Show abstract][Hide abstract] ABSTRACT: Acute respiratory illnesses (ARIs) are the leading cause of medical visits for community-dwelling patients of all ages, but virologic and clinical descriptions of these illnesses in older adults are infrequent.
To determine the feasibility of influenza surveillance in a population of community-dwelling elderly, to compare the patterns of influenza infection in elderly persons with that observed in young populations in which surveillance is usually conducted, and to describe the clinical presentation of influenza infection in elderly outpatients who seek medical attention for ARI.
Prospective clinical and viral surveillance of ARIs among ambulatory patients during 3 consecutive winter seasons.
Nine internal medicine and 3 pediatric practices in Upstate New York in cooperation with the Medicare Influenza Vaccine Demonstration Project.
Elderly (n=808) and pediatric (n=2080) outpatients with ARI office visits.
Frequency of influenza and other respiratory virus isolates and clinical profile of influenza among older adults and children with ARIs.
Influenza virus was the viral agent recovered most often from specimens obtained from patients in both age groups with ARI symptoms, especially those with fever. Influenza accounted for 11% of ARIs in adults (87 isolates) and 20% in children (408 isolates). At the initial illness visit, influenza infection was equally common in elderly individuals with or without underlying cardiopulmonary conditions. Lower respiratory tract signs occurred in 13% of the adults and in 7% of the children with influenza documented by laboratory studies. Other respiratory viruses were recovered from specimens obtained from 20 adults and from 259 children.
Viruses are important agents of ARIs in elderly outpatients. Children and older adults experience similar patterns of influenza infection and other epidemic respiratory pathogens, such as parainfluenza and respiratory syncytial viruses. Viral identification is feasible in older adults seen in physicians' offices and may contribute to improved measures of effects of influenza and other respiratory viruses on ARIs.
Preview · Article · Sep 1997 · Archives of Family Medicine
[Show abstract][Hide abstract] ABSTRACT: Human herpesvirus 6 (HHV-6) causes a febrile illness in children and has been implicated as a cause of encephalitis and recurrent
seizures. Paired samples of cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) from 487 children were
evaluated by nested polymerase chain reaction (PCR) for evidence of current or past infection with HHV-6. PBMC were also cultured
for isolation of HHV-6. These data were correlated with the patients' clinical information. HHV-6 DNA was detected in 72 (14.8%)
of 487 CSF samples. HHV-6 persistence was documented in 142 children by PCR detection ofHHV-6 DNA in PBMC or CSF (or both)
in the absence of primary HHV-6 infection; the central nervous system was the only site of HHV-6 DNA persistence in 28.9%.
HHV-6 DNA can be detected in the CSF of children during and after primary infection, and the central nervous system may be
the sole site of persistence.
No preview · Article · Jan 1995 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Infection with human herpesvirus-6 (HHV-6) is nearly universal in infancy or early childhood. However, the course of this infection, its complications, and its potential for persistence or reactivation remain unclear.
We studied infants and children under the age of three years who presented to our emergency department with acute illnesses. Infants and young children without acute illness were studied as controls. HHV-6 infection was identified by blood-mononuclear-cell culture, serologic testing, and the polymerase chain reaction (PCR).
No primary HHV-6 infection was found among 582 infants and young children with acute nonfebrile illnesses or among 352 controls without acute illness. Of 1653 infants and young children with acute febrile illnesses, 160 (9.7 percent) had primary HHV-6 infection, as documented by viremia and seroconversion. They ranged in age from 2 weeks to 25 months; 23 percent were under the age of 6 months. HHV-6 infections accounted for 20 percent of 365 visits to the emergency department for febrile illnesses among children 6 to 12 months old. Of the 160 infants and young children with acute HHV-6 infections, 21 (13 percent) were hospitalized, and 21 had seizures. Often the seizures appeared late and were prolonged or recurrent. HHV-6 infections accounted for one third of all febrile seizures in children up to the age of two years. In follow-up studies over a period of one to two years, the HHV-6 genome persisted in blood mononuclear cells after primary infection in 37 of 56 children (66 percent). Reactivation, sometimes with febrile illnesses, was suggested by subsequent increases in antibody titers in 16 percent (30 of 187) and by PCR in 6 percent (17 of 278). No recurrent viremia was detected. Of 41 healthy newborns studied, 12 (29 percent) had the HHV-6 genome in their blood mononuclear cells; nevertheless, 6 of these newborns subsequently had primary HHV-6 infections.
In infants and young children HHV-6 infection is a major cause of visits to the emergency department, febrile seizures, and hospitalizations. Perinatal transmission may occur, with possible asymptomatic, transient, or persistent neonatal infection.
Preview · Article · Sep 1994 · New England Journal of Medicine
[Show abstract][Hide abstract] ABSTRACT: Two variants of human herpesvirus 6 were identified. To assess their epidemiology and disease association, we analyzed viral isolates and/or uncultured peripheral blood mononuclear cells from 76 infants with symptomatic primary infection. In 97% of cases, human herpesvirus 6 variant B was detected, but variant A was not.
Preview · Article · Mar 1993 · Journal of Clinical Microbiology