Effectiveness of seasonal influenza vaccines in the United States during a season with circulation of all three vaccine strains.

Background: Influenza vaccines may be reformulated annually because of antigenic drift in influenza viruses. However, the relationship between antigenic characteristics of circulating viruses and vaccine effectiveness (VE) is not well understood. We conducted an assessment of the effectiveness of US influenza vaccines during the 2010-2011 season.

Diagnostic assays for active infection with human herpesvirus 6 (HHV-6).

Background: 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.

Transplacental congenital human herpesvirus 6 infection caused by maternal chromosomally integrated virus.

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.

Vaccine effectiveness against laboratory-confirmed influenza in children 6 to 59 months of age during the 2003-2004 and 2004-2005 influenza seasons.

Objective: The goal was to estimate the effectiveness of influenza vaccination against laboratory-confirmed influenza during the 2003-2004 and 2004-2005 influenza seasons in children 6 to 59 months of age.

Methods: We conducted a case-control study with children with medically attended, acute respiratory infections who received care in an inpatient, emergency department, or outpatient clinic setting during 2 consecutive influenza seasons. All children residing in Monroe County, New York, Davidson County, Tennessee, or Hamilton County, Ohio, were enrolled prospectively at the time of acute illness and had nasal/throat swabs tested for influenza with cultures and/or polymerase chain reaction assays.

Influenza vaccine effectiveness among children 6 to 59 months of age during 2 influenza seasons: a case-cohort study.

Objective: To measure vaccine effectiveness (VE) in preventing influenza-related health care visits among children aged 6 to 59 months during 2 consecutive influenza seasons.

Design: Case-cohort study estimating effectiveness of inactivated influenza vaccine in preventing inpatient/outpatient visits (emergency department [ED] and outpatient clinic). We compared vaccination status of laboratory-confirmed influenza cases with a cluster sample of children from a random sample of practices in 3 counties (subcohort) during the 2003-2004 and 2004-2005 seasons.

Chromosomal integration of human herpesvirus 6 is the major mode of congenital human herpesvirus 6 infection.

Objective: We examined the frequency and characteristics of chromosomally integrated human herpesvirus 6 among congenitally infected children.

Methods: 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 (HHV)-6 and HHV-7 infections in pregnant women.

Background: Both intrauterine and sexual transmission of human herpesvirus (HHV)-6 and HHV-7 have been suggested, and congenital HHV-6 infection does occur. We prospectively studied HHV-6 and HHV-7 at multiple sites in pregnant women to determine the characteristics of these viruses at repeated time points.

Methods: Peripheral blood mononuclear cells (PBMCs), cervical secretions, placenta, and cord blood were tested by nested polymerase chain reaction (PCR) and reverse-transcriptase PCR for HHV-6 and HHV-7 and by quantitative PCR for HHV-6.

Characteristics and acquisition of human herpesvirus (HHV) 7 infections in relation to infection with HHV-6.

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 < or =10 years old, HHV-7 and HHV-6 infections and their interaction by serologic assessment, viral isolation, and polymerase chain reaction.

Human herpesvirus 6 (HHV6) DNA persistence and reactivation in healthy children.

Objective: 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.

Study Design: 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.

Congenital infections with human herpesvirus 6 (HHV6) and human herpesvirus 7 (HHV7).

Objective: 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.

Study Design: 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.

Results: HHV6 DNA was detected in 57 (1%) of 5638 cord bloods.

Seven-year follow-up of vaccine response in extremely premature infants.

Objective: To assess the immune response of 7-year-old former extremely preterm (PT) infants to routine childhood immunizations.

Methods: Sixteen PT (<29 weeks and <1000 g) infants, followed since their primary immunizations at the recommended chronological ages, and 16 age-matched full-term (FT) control subjects were evaluated at 7 years of age. Antibodies to Haemophilus influenzae type b polyribosylribitol phosphate (Hib-PRP), tetanus, pertussis, diphtheria, polio, and hepatitis B (HBsAb) were measured.