Effectiveness of 2 doses of varicella vaccine in children.

BACKGROUND: Because of ongoing outbreaks of varicella, a second dose of varicella vaccine was added to the routine immunization schedule for children in June 2006 by the Centers for Disease Control and Prevention. METHODS: We assessed the effectiveness of 2 doses of varicella vaccine in a case-control study by identifying children ≥4 years of age with varicella confirmed by polymerase chain reaction assay and up to 2 controls matched by age and pediatric practice. Effectiveness was calculated using exact conditional logistic regression. RESULTS: From July 2006 to January 2010, of the 71 case subjects and 140 matched controls enrolled, no cases (0%) vs 22 controls (15.7%) had received 2 doses of varicella vaccine, 66 cases (93.0%) vs 117 controls (83.6%) had received 1 dose, and 5 cases (7.0%) vs 1 control (0.7%) did not receive varicella vaccine (P < .001). The effectiveness of 2 doses of the vaccine was 98.3% (95% confidence level [CI]: 83.5%-100%; P < .001). The matched odds ratio for 2 doses vs 1 dose of the vaccine was 0.053 (95% CI: 0.002-0.320; P < .001). CONCLUSION: The effectiveness of 2 doses of varicella vaccine in the first 2.5 years after recommendation of a routine second dose of the vaccine for children is excellent. Odds of developing varicella were 95% lower for children who received 2 doses compared with 1 dose of varicella vaccine.

Respiratory Pathogens in Children 1 Month to 5 Years of Age Presenting With Undifferentiated Acute Respiratory Distress in 2 District-Level Hospitals in Ghana.

Ghanaian children (2176) aged <5 years who presented with undifferentiated acute respiratory distress were tested for respiratory pathogens using a BioFire FilmArray polymerase chain reaction assay. Rhinovirus and/or enterovirus was detected in 36% of the assays, respiratory syncytial virus in 11%, and parainfluenza in 7%. Respiratory syncytial virus and metapneumovirus were detected more frequently in the rainy season than in the dry season.

Feasibility of Text Message Influenza Vaccine Safety Monitoring During Pregnancy.

INTRODUCTION: The feasibility and accuracy of text messaging to monitor events after influenza vaccination throughout pregnancy and the neonatal period has not been studied, but may be important for seasonal and pandemic influenza vaccines and future maternal vaccines. METHODS: This prospective observational study was conducted during 2013-2014 and analyzed in 2015-2016. Enrolled pregnant women receiving inactivated influenza vaccination at a gestational age <20 weeks were sent text messages intermittently through participant-reported pregnancy end to request fever, health events, and neonatal outcomes. Text message response rates, Day 0-2 fever (≥100.4°F), health events, and birth/neonatal outcomes were assessed. RESULTS: Most (80.2%, n=166) eligible women enrolled. Median gestational age was 8.9 (SD=3.9) weeks at vaccination. Response rates remained high (80.0%-95.2%). Only one Day 0-2 fever was reported. Women reported via text both pregnancy- and non-pregnancy-specific health events, not all associated with medical visits. Most pregnancy-specific events in the electronic medical record (EMR) were reported via text message. Of all enrollees, 84.9% completed the study (131 reported live birth, ten reported pregnancy loss). Two losses reported via text were not medically attended; there was one additional EMR-identified loss. Gestational age and weight at birth were similar between text message-reported and EMR-abstracted data and 95% CIs were overlapping for proportions of prematurity, low birth weight, small for gestational age, and major birth defects, as identified by text message-reported versus EMR-abstracted plus text message-reported versus EMR-abstracted data only. CONCLUSIONS: This study demonstrated the feasibility of text messaging for influenza vaccine safety surveillance sustained throughout pregnancy. In these women receiving inactivated influenza vaccination during pregnancy, post-vaccination fever was infrequent and a typical pattern of maternal and neonatal health outcomes was observed.

Arm Paralysis After Routine Childhood Vaccinations: Application of Advanced Molecular Methods to the Causality Assessment of an Adverse Event After Immunization.

Post-licensure surveillance for adverse events following immunizations (AEFI) can identify rare complications of vaccinations and rigorous vaccine adverse event causality assessments can help to identify possible causal relationships. We report the development of arm paralysis after varicella vaccination in a 1-year-old child. Paralysis was initially presumed to be due to vOka because of the temporal relationship between vaccination and onset of arm weakness; however, molecular studies identified wild-type varicella zoster virus VZV (WT-VZV) in the CSF, leading the authors to conclude that WT-VZV was the probable cause. This case illustrates the complexity of assessing AEFI causality, and the importance of careful and complete evaluations when determining the most likely cause of an AEFI.

Antiretroviral resistance in viral isolates from HIV-1-transmitting mothers and their infants.

OBJECTIVE: To characterize concordance of resistance mutations to antiretroviral drugs (ART) in mother-infant pairs. DESIGN: Case series of HIV-transmitting mothers and infants in the Women and Infants Transmission Study, where delivery occurred between April 1994 and December 1999. METHODS: Reverse transcriptase and protease genes were sequenced in stored viral isolates from 32 mother-infant pairs. Mutations were coded as "pure mutants" where only mutant virus was detected or as "mixtures" where a mixed mutant/wild-type population was identified. ART resistance mutations were compared for concordance between mothers and their infants. RESULTS: Maternal mutations associated with resistance to nucleoside reverse transcriptase inhibitor (NRTI) and minor protease inhibitor (PI) drugs were typically concordant with that of infant, while those associated with non-nucleoside reverse transcriptase inhibitors (NNRTI) and major PI drugs were not. Of five NRTI-associated maternal mutations observed, three pure mutants corresponded with mutant in the infant, while two wild-type-predominant mixtures corresponded with infant wild type. The only NNRTI-associated mutation observed, K103N, was not transmitted, nor were the two major PI-associated mutations, L90M and V82I/V. Transmission of minor PI-associated mutations was consistent with the sole observed or dominant variant for 20 of 21 mutations. CONCLUSIONS: For NRTI- and minor PI-associated mutations, transmission was consistent with relative quantity of variants in maternal virus. However, where NNRTI- and major PI-associated mutations were present in three cases, they were not transmitted, even where only mutant virus was detectable in maternal isolates. This is consistent with evidence of loss of transmission with resistance to NNRTI and PI drugs.

The impact of DTaP-IPV-HB vaccine on use of health services for young infants.

BACKGROUND: In 2003, a pentavalent vaccine (diphtheria, tetanus and acellular pertussis, injectable polio and hepatitis B) was introduced into the childhood vaccination schedule. A premarketing study showed a higher incidence of fever than with the vaccines administered separately. Because fevers in young infants prompt medical evaluations, this study examines the impact of this vaccine (DTaP-IPV-HB) on subsequent use of health services. METHODS: We compared use of health services among 6- to 10-week-old infants receiving DTaP-IPV-HB (n = 1776) with a historical control receiving the prior schedule (n = 2162) at an inner-city practice network. Data sources included a hospital immunization registry and medical records. Outcome measures were visits to the emergency department and ambulatory practices, fever, tests, antibiotics and hospitalizations. Outcomes were stratified by age (<8, 8-10 weeks) and days since vaccination (3, 7). RESULTS: Infants vaccinated with DTaP-IPV-HB were more likely to visit the ED (1.2% versus 0.6%, P = 0.03) and receive tests (47.6% versus 8.3%, P = 0.03) within 3 days of vaccination compared with the controls. Multivariate analysis showed infants vaccinated with DTaP-IPV-HB had a 7-fold increased risk of receiving a full sepsis workup and a 3-fold increased risk of receiving antibiotics within 7 days of vaccination. Medical evaluations decreased over time after implementation of the DTaP-IPV-HB vaccine. Concurrently, the rate of vaccination for infants <8 weeks markedly dropped. CONCLUSIONS: The DTaP-IPV-HB vaccine was associated with increased use of health services in the emergency department, but these associations lessened over time. These findings reveal a conflict between the obligation of timely and efficient vaccination with the medical management of febrile young infants.

Effectiveness over time of varicella vaccine.

CONTEXT: Reports of outbreaks of varicella in highly immunized groups have increased concern about the effectiveness of varicella vaccine. OBJECTIVE: To assess whether the effectiveness of varicella vaccine is affected either by time since vaccination or by age at the time of vaccination. DESIGN: Case-control study conducted from March 1997 through June 2003. SETTING: Twenty different group practices in southern Connecticut. PARTICIPANTS: Case subjects, identified by active surveillance of all practices, consisted of 339 eligible children 13 months or older who were clinically diagnosed as having chickenpox and who also had a polymerase chain reaction (PCR) test result that was positive for varicella-zoster virus DNA. For each case subject, 2 controls were selected, matched by both age and pediatric practice. MAIN OUTCOME MEASURES: The effectiveness of the vaccine, especially the effects of time since vaccination and age at the time of vaccination, adjusted for possible confounders. RESULTS: Although the adjusted overall effectiveness of the vaccine was 87% (95% confidence interval, 81%-91%; P<.001), there was a substantial difference in the vaccine's effectiveness in the first year after vaccination (97%) and in years 2 to 8 after vaccination (84%, P =.003). The vaccine's effectiveness in year 1 was substantially lower if the vaccine was administered at younger than 15 months (73%) than if it was administered at 15 months or older (99%, P =.01), although the difference in effectiveness overall for children immunized at younger than 15 months was not statistically significantly different than for those immunized at 15 months or older (81% vs 88%, P =.17). Most cases of chickenpox in vaccinees were mild. CONCLUSIONS: Although varicella vaccine is effective, its effectiveness decreases significantly after 1 year, although most cases of breakthrough disease are mild. If administered at younger than 15 months, the vaccine's effectiveness was lower in the first year after vaccination, but the difference in effectiveness was not statistically significant for subsequent years.

Immediate hypersensitivity reactions following monovalent 2009 pandemic influenza A (H1N1) vaccines: reports to VAERS.

BACKGROUND: Hypersensitivity disorders following vaccinations are a cause for concern. OBJECTIVE: To determine the type and rate by age, gender, and vaccine received for reported hypersensitivity reactions following monovalent 2009 pandemic influenza A (H1N1) vaccines. DESIGN: A systematic review of reports to the Vaccine Adverse Event Reporting System (VAERS) following monovalent 2009 pandemic influenza A (H1N1) vaccines. SETTING/PATIENTS: US Civilian reports following vaccine received from October 1, 2009 through May 31, 2010. MEASUREMENTS: Age, gender, vaccines received, diagnoses, clinical signs, and treatment were reviewed by nurses and physicians with expertise in vaccine adverse events. A panel of experts, including seven allergists reviewed complex illnesses and those with conflicting evidence for classification of the event. RESULTS: Of 1984 reports, 1286 were consistent with immediate hypersensitivity disorders and 698 were attributed to anxiety reactions, syncope, or other illnesses. The female-to-male ratio was ≥4:1 for persons 20-to-59 years of age, but approximately equal for children under 10. One hundred eleven reports met Brighton Collaboration criteria for anaphylaxis; only one-half received epinephrine for initial therapy. The overall rate of reported hypersensitivity reactions was 10.7 per million vaccine doses distributed, with a 2-fold higher rate for live vaccine. LIMITATIONS: Underreporting, especially of mild events, would result in an underestimate of the true rate of immediate hypersensitivity reactions. Selective reporting of events in adult females could have resulted in higher rates than reported for males. CONCLUSIONS: Adult females may be at higher risk of hypersensitivity reactions after influenza vaccination than men. Although the risk of hypersensitivity reactions following 2009 pandemic influenza A (H1N1) vaccines was low, all clinics administering vaccines should be familiar with treatment guidelines for these adverse events, including the use of intramuscular epinephrine early in the course of serious hypersensitivity reactions.

Understanding the role of human variation in vaccine adverse events: the Clinical Immunization Safety Assessment Network.

The Clinical Immunization Safety Assessment (CISA) Network is a collaboration between the Centers for Disease Control and Prevention (CDC) and 6 academic medical centers to provide support for immunization safety assessment and research. The CISA Network was established by the CDC in 2001 with 4 primary goals: (1) develop research protocols for clinical evaluation, diagnosis, and management of adverse events following immunization (AEFI); (2) improve the understanding of AEFI at the individual level, including determining possible genetic and other risk factors for predisposed people and subpopulations at high risk; (3) develop evidence-based algorithms for vaccination of people at risk of serious AEFI; and (4) serve as subject-matter experts for clinical vaccine-safety inquiries. CISA Network investigators bring in-depth clinical, pathophysiologic, and epidemiologic expertise to assessing causal relationships between vaccines and adverse events and to understanding the pathogenesis of AEFI. CISA Network researchers conduct expert reviews of clinically significant adverse events and determine the validity of the recorded diagnoses on the basis of clinical and laboratory criteria. They also conduct special studies to investigate the possible pathogenesis of adverse events, assess relationships between vaccines and adverse events, and maintain a centralized repository for clinical specimens. The CISA Network provides specific clinical guidance to both health care providers who administer vaccines and those who evaluate and treat patients with possible AEFI. The CISA Network plays an important role in providing critical immunization-safety data and expertise to inform vaccine policy-makers. The CISA Network serves as a unique resource for vaccine-safety monitoring efforts conducted at the CDC.

Overview of the Clinical Consult Case Review of adverse events following immunization: Clinical Immunization Safety Assessment (CISA) network 2004-2009.

BACKGROUND: In 2004 the Clinical Consult Case Review (CCCR) working group was formed within the CDC-funded Clinical Immunization Safety Assessment (CISA) Network to review individual cases of adverse events following immunizations (AEFI). METHODS: Cases were referred by practitioners, health departments, or CDC employees. Vaccine Adverse Event Reporting System (VAERS) searches and literature reviews for similar cases were performed prior to review. After CCCR discussion, AEFI were assessed for a causal relationship with vaccination and recommendations regarding future immunizations were relayed back to the referring physicians. In 2010, surveys were sent to referring physicians to determine the utility and effectiveness of the CCCR service. RESULTS: CISA investigators reviewed 76 cases during 68 conference calls between April 2004 and December 2009. Almost half of the cases (35/76) were neurological in nature. Similar AEFI for the specific vaccines received were discovered for 63 cases through VAERS searches and for 38 cases through PubMed searches. Causality assessment using the modified WHO criteria resulted in classifying 3 cases as definitely related to vaccine administration, 12 as probably related, 16 as possibly related, 18 as unlikely related, 10 as unrelated, and 17 had insufficient information to assign causality. The physician satisfaction survey was returned by 30 (57.7%) of those surveyed and a majority of respondents (93.3%) felt that the CCCR service was useful. CONCLUSIONS: The CCCR provides advice about AEFI to practitioners, assigns potential causality, and contributes to an improved understanding of adverse health events following immunizations.

Causality assessment of serious neurologic adverse events following 2009 H1N1 vaccination.

BACKGROUND: Adverse events occurring after vaccination are routinely reported to the Vaccine Adverse Event Reporting System (VAERS). We studied serious adverse events (SAEs) of a neurologic nature reported after receipt of influenza A (H1N1) 2009 monovalent vaccine during the 2009-2010 influenza season. Investigators in the Clinical Immunization Safety Assessment (CISA) network sought to characterize these SAEs and to assess their possible causal relationship to vaccination. METHODS: Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) physicians reviewed all SAE reports (as defined by the Code of Federal Regulations, 21CFR§314.80) after receipt of H1N1 vaccine reported to VAERS between October 1, 2009 and March 31, 2010. Non-fatal SAE reports with neurologic presentation were referred to CISA investigators, who requested and reviewed additional medical records and clinical information as available. CISA investigators assessed the causal relationship between vaccination and the event using modified WHO criteria as defined. RESULTS: 212 VAERS reports of non-fatal serious neurological events were referred for CISA review. Case reports were equally distributed by gender (50.9% female) with an age range of 6 months to 83 years (median 38 years). The most frequent diagnoses reviewed were: Guillain-Barré Syndrome (37.3%), seizures (10.8%), cranial neuropathy (5.7%), and acute disseminated encephalomyelitis (3.8%). Causality assessment resulted in classification of 72 events as "possibly" related (33%), 108 as "unlikely" related (51%), and 20 as "unrelated" (9%) to H1N1 vaccination; none were classified as "probable" or "definite" and 12 were unclassifiable (6%). CONCLUSION: The absence of a specific test to indicate whether a vaccine component contributes to the pathogenesis of an event occurring within a biologically plausible time period makes assessing causality difficult. The development of standardized protocols for providers to use in evaluation of adverse events following immunization, and rapid identification and follow-up of VAERS reports could improve causality assessment.

A phase I-II study of live attenuated varicella-zoster virus vaccine to boost immunity in human immunodeficiency virus-infected children with previous varicella.

Herpes zoster, may be severe and recurrent in HIV-infected children. We determined the safety and immunogenicity of live attenuated varicella-zoster virus (VZV) vaccine in 46 HIV-infected children who had experienced varicella. There were no serious adverse events. Two years after vaccination 82% of subjects remained VZV-antibody positive and 60% had VZV-specific cell-mediated immunity. No child developed herpes zoster.

Risk of herpes zoster in adults immunized with varicella vaccine.

A program of routine varicella vaccination of children 12-18 months of age, begun in the United States in 1995, has been very successful in reducing the incidence of varicella. Varicella-zoster virus (VZV), in both wild-type and live attenuated forms, is notable for its ability to produce latent infection of sensory neurons from which it can later reactivate to cause herpes zoster (HZ). Therefore, the effects of vaccination on this secondary VZV-related disease are important to consider; in practice, however, such studies are complicated by the typically long delay between acquisition of the virus and its reactivation. Studies of immunocompromised children have shown that vaccination is relatively protective against HZ in this highly vulnerable group. We now present long-term follow-up data on a group of individuals who received varicella vaccine as healthy young adults 10-26 years ago and who have been followed prospectively by means of active surveillance. Among some 2000 person-years of follow-up, 2 cases of HZ have occurred, for a rate of 1.00 case/1000 person-years. Overall, the incidence of HZ in this cohort, therefore, is similar to published data for the US population in the prevaccine era.

The safety profile of varicella vaccine: a 10-year review.

Varivax (varicella virus vaccine live [Oka/Merck]; Merck), a live attenuated varicella vaccine, is indicated for vaccination against varicella in appropriate individuals > or =12 months of age. The 10-year safety profile for Varivax is described using data submitted to Merck from routine global postmarketing surveillance, combined with information from a Varicella Zoster Virus Identification Program, which uses polymerase chain reaction (PCR) analysis to identify the presence and strain of VZV in selected specimens. There were 16,683 reports worldwide voluntarily submitted to Merck, for an overall reporting rate of 3.4 reports/10,000 doses of vaccine distributed. PCR analysis of vesicular rashes that occurred within the first 2 weeks after vaccination was more likely to identify wild-type varicella-zoster virus (VZV), whereas the presence of Oka VZV was generally associated with vesicular rashes that occurred 15-42 days after vaccination. Reports of breakthrough varicella that occurred >42 days after vaccination were associated with wild-type VZV. Among 697 herpes zoster reports, PCR analysis identified Oka VZV in 57 reports and wild-type VZV in 38 reports. There were no primary neurologic adverse events associated with Oka VZV. Secondary transmission of Oka VZV from vaccine recipients with postvaccination vesicular rashes was identified in 3 susceptible household contacts. Disseminated Oka VZV was identified in 6 immunocompromised patients and 1 patient with Down syndrome. This review has shown that the vaccine is generally safe and well tolerated.

Primary vaccine failure after 1 dose of varicella vaccine in healthy children.

Universal immunization of young children with 1 dose of varicella vaccine was recommended in the United States in 1995, and it has significantly decreased the incidence of chickenpox. Outbreaks of varicella, however, are reported among vaccinated children. Although vaccine effectiveness has usually been 85%, rates as low as 44% have been observed. Whether this is from primary or secondary vaccine failure-or both-is unclear. We tested serum samples from 148 healthy children immunized against varicella in New York, Tennessee, and California to determine their seroconversion rates, before and after 1 dose of Merck/Oka varicella vaccine. The median age at vaccination was 12.5 months; postvaccination serum samples were obtained on average 4 months later. Serum was tested for antibodies against varicella-zoster virus (VZV) by use of the previously validated sensitive and specific fluorescent antibody to membrane antigen (FAMA) assay. Of 148 healthy child vaccinees, 113 (76%) seroconverted, and 24% had no detectable VZV FAMA antibodies. Our data contrast with reported seroconversion rates of 86%-96% by other VZV antibody tests and suggest that many cases of varicella in immunized children are due to primary vaccine failure. A second dose of varicella vaccine is expected to increase seroconversion rates and vaccine effectiveness.

Time trends for HIV-1 antiretroviral resistance among antiretroviral-experienced and naive pregnant women in New York City during 1991 to early 2001.

Time trends in the prevalence of drug resistance to antiretroviral therapy (ART) in pregnant women have not been studied. Treatment and prophylactic efficacy could be compromised by drug-resistant HIV strains. We conducted a repeated cross-sectional study of antiretroviral resistance mutations to nucleoside reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) and of major mutations to protease inhibitors (PIs) in virus isolates from 300 HIV-infected pregnant women in New York City from 1991 to early 2001. The overall prevalence of mutations for NRTIs from 1991 to early 2001 was higher for ART-experienced (25.6% [95% confidence interval (CI): 19.1% to 32.1%]) than ART-naive (8.6% [95% CI: 3.7% to 13.4%]) mothers (P < 0.002). For NNRTIs, the overall prevalence of mutations was somewhat higher among ART-experienced (5.8% [95% CI: 2.3% to 9.3%]) versus ART-naive (1.6% [95% CI: 0% to 3.7%]) women (P = 0.06), and increased over time for ART-naive women (0%-7.4%; P = 0.03) and ART-experienced women (0%-19.4%; P = 0.0002). The prevalence of PI-associated mutations was also higher overall among ART-experienced mothers (5.8% [95% CI: 2.3% to 9.3%] vs. 1.6% [95% CI: 0% to 3.7%]; P = 0.06), with increases over time seen for ART-naive women (0%-7.4%; P = 0.03) and ART-experienced women (0%-16.1%; P = 0.0008). The increasing prevalence of drug resistance in pregnant women, including those who are drug-naive, underscores the necessity for resistance testing to guide treatment to achieve suppression of the mother's virus.

Severe varicella caused by varicella-vaccine strain in a child with significant T-cell dysfunction.

In March 1995, the US Food and Drug Administration approved a live attenuated varicella vaccine for use in healthy children 12 months to 12 years old. We report here an 18-month-old girl with cell-mediated immunodeficiency who developed a severe vaccine-associated rash and clinical evidence of vaccine-associated pneumonia 1 month after inadvertent receipt of varicella vaccine.

Predictors of repeat pregnancy among HIV-1-infected women.

BACKGROUND: In the Women and Infants Transmission Study (WITS), a prospective cohort study of HIV-infected pregnant women at six US mainland and Puerto Rican sites, changes in the HIV-1 epidemic have included higher income, better education, and better-controlled HIV disease among more recently enrolled women. Because these changes may alter the reproductive patterns of these women an awareness of these women's current reproductive behaviors is essential. We examined predictors of repeat pregnancy among HIV-1-infected women enrolled in the Women and Infants Transmission Study (WITS). METHODS: Women enrolled in WITS without a history of sterilization were included. Using bivariate and multivariate analyses, predictors of a repeat pregnancy were modeled. Changes in risk factors for repeat pregnancy over time were examined and important predictors of repeat pregnancy were determined. RESULTS: Of 2246 eligible women, 22% had more than one WITS-enrolled pregnancy. In bivariate analyses, risk of repeat pregnancy was associated with younger age, lower educational status, higher CD4%, and lower viral loads. There was little change in risk factors for repeat pregnancy over time. CONCLUSIONS: HIV-1-infected women who are younger and healthier are more likely to have more than one pregnancy. Factors associated with repeat pregnancy among HIV-1-infected women have remained stable over time. Awareness of these factors will better equip healthcare providers to address the reproductive needs of HIV-1-infected women.