Live attenuated tetravalent (G1-G4) bovine-human reassortant rotavirus vaccine (BRV-TV): Randomized,controlled phase III study in Indian infants

BackgroundRotavirus remains the leading cause of diarrhoea among children <5 years. We assessed immunogenic non-inferiority of a tetravalent bovine-human reassortant rotavirus vaccine (BRV-TV) over the licensed human-bovine pentavalent rotavirus vaccine RV5.MethodsPhase III single-blind study (parents blinded) in healthy infants randomized (1:1) to receive three doses of BRV-TV or RV5 at 6–8, 10–12, and 14–16 weeks of age. All concomitantly received a licensed diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b conjugate vaccine (DTwP-HepB-Hib) and oral polio vaccine (OPV). Immunogenic non-inferiority was evaluated in terms of the inter-group difference in anti-rotavirus serum IgA seroresponse (primary endpoint), and seroprotection/seroresponse rates to DTwP-HepB-Hib and OPV vaccines. Seroresponse was defined as a ≥4-fold increase in titers from baseline to D28 post-dose 3. Non-inferiority was declared if the difference between groups (based on the lower limit of the 95% confidence interval [CI]) was above −10%. Each subject was evaluated for solicited adverse events 7 days and unsolicited & serious adverse events 28 days following each dose of vaccination.ResultsOf 1195 infants screened, 1182 were randomized (590 to BRV-TV; 592 to RV5). Non-inferiority for rotavirus serum IgA seroresponse was not established: BRV-TV, 47.1% (95%CI: 42.8; 51.5) versus RV5, 61.2% (95%CI: 56.8; 65.5); difference between groups, −14.08% (95%CI: −20.4; −7.98). Serum IgA geometric mean concentrations at D28 post-dose 3 were 28.4 and 50.1 U/ml in BRV-TV and RV5 groups, respectively. For all DTwP-HepB-Hib and OPV antigens, seroprotection/seroresponse was elicited in both groups and the −10% non-inferiority criterion between groups was met. There were 16 serious adverse events, 10 in BRV-TV group and 6 in RV5 group; none were classified as vaccine related. Both groups had similar vaccine safety profiles.ConclusionBRV-TV was immunogenic but did not meet immunogenic non-inferiority criteria to RV5 when administered concomitantly with routine pediatric antigens in infants.     

Efficacy and safety of a pentavalent live human-bovine reassortant rotavirus vaccine (RV5) in healthy Chinese infants: A randomized,double-blind,placebo-controlled trial

BackgroundA randomized, double-blind, placebo-controlled multicenter trial was conducted in healthy Chinese infants to assess the efficacy and safety of a pentavalent live human-bovine reassortant rotavirus vaccine (RotaTeq™, RV5) against rotavirus gastroenteritis (RVGE).Methods4040 participants aged 6–12 weeks were enrolled and randomly assigned to either 3 oral doses of RV5 (n = 2020) or placebo (n = 2020), administered ∼4 weeks apart. The participants also received OPV and DTaP in a concomitant or staggered fashion. The primary objective was to evaluate vaccine efficacy (VE) against naturally-occurring RVGE at least 14 days following the third dose. Key secondary objectives included: VE against naturally-occurring severe RVGE and VE against severe and any-severity RVGE caused by rotavirus serotypes contained in the vaccine, occurring at least 14 days after the third dose. All adverse events (AEs) were collected for 30 days following each dose. Serious AEs (SAEs) and intussusception cases were collected during the entire study. (ClinicalTrials.gov registry: NCT02062385).ResultsVE against RVGE of any-severity caused by any serotype was 69.3% (95% CI: 54.5, 79.7). The secondary efficacy analysis showed an efficacy of: 78.9% (95% CI: 59.1, 90.1) against severe RVGE caused by any serotype; 69.9% (95% CI: 55.2, 80.3) and 78.9% (95% CI: 59.1, 90.1) against any-severity and severe RVGE caused by serotypes contained in the vaccine, respectively. Within 30 days following any vaccination, 53.5% (1079/2015) and 53.3% (1077/2019) of participants reported at least one AE, and 5.8% (116/2015) and 5.7% (116/2019) reported SAEs in the vaccine and placebo groups, respectively. No SAEs were considered vaccine-related in recipients of RV5. Two intussusception cases were reported in recipients of RV5 who recovered after receiving treatment. Neither was considered vaccine-related.ConclusionsIn Chinese infants, RV5 was efficacious against any-severity and severe RVGE caused by any serotype and generally well-tolerated with respect to AEs.     

Safety and immunogenicity of a parenterally administered rotavirus VP8 subunit vaccine in healthy adults

BackgroundThe P2-VP8 subunit vaccine for the prevention of rotavirus gastroenteritis is comprised of a truncated VP8 subunit protein from the rotavirus Wa strain (G1[P8]) fused to the tetanus toxin P2 epitope, and adsorbed on aluminum hydroxide for intramuscular administration.MethodsThree groups of 16 adults were randomized to receive three injections of P2-VP8 (12) or placebo (4) at doses of 10, 30 or 60 μg of vaccine. IgG and IgA antibodies to P2-VP8 were assessed by ELISA in serum and lymphocyte supernatant (ALS). Serum samples were tested for neutralizing antibodies to homologous and heterologous strains of rotavirus.ResultsThe vaccine was well-tolerated. All vaccine recipients demonstrated significant IgA responses and all but one demonstrated IgG responses; in the 60 μg cohort, geometric mean titers (GMTs) rose 70- and 80-fold for IgA and IgG, respectively. Homologous neutralizing antibody responses were observed in about half of participants in all three dose cohorts; in the 60 μg cohort, GMTs against Wa rose from 128 to 992. Neutralizing antibody responses were robust to P[8] strains, moderate to P[4] strains and negligible to P[6] strains. ALS IgA responses were dose dependent.ConclusionsThe P2-VP8 subunit vaccine was well tolerated and evoked promising immune responses.Clinical trials registrationNCT01764256     

The effect of probiotics and zinc supplementation on the immune response to oral rotavirus vaccine: A randomized,factorial design,placebo-controlled study among Indian infants

BackgroundStrategies are needed to improve oral rotavirus vaccine (RV), which provides suboptimal protection in developing countries. Probiotics and zinc supplementation could improve RV immunogenicity by altering the intestinal microbiota and immune function.MethodsInfants 5 weeks old living in urban Vellore, India were enrolled in a randomized, double-blind, placebo-controlled trial with a 4-arm factorial design to assess the effects of daily zinc (5 mg), probiotic (10¹⁰ Lactobacillus rhamnosus GG) or placebo on the immunogenicity of two doses of RV (Rotarix®, GlaxoSmithKline Biologicals) given at 6 and 10 weeks of age. Infants were eligible for participation if healthy, available for the study duration and without prior receipt of RV or oral poliovirus vaccine other than the birth dose. The primary outcome was seroconversion to rotavirus at 14 weeks of age based on detection of VP6-specific IgA at ≥20 U/ml in previously seronegative infants or a fourfold rise in concentration.ResultsThe study took place during July 2012 to February 2013. 620 infants were randomized equally between study arms and 551 (88.9%) completed per protocol. Seroconversion was recorded in 54/137 (39.4%), 42/136 (30.9%), 40/143 (28.0%), and 37/135 (27.4%) infants receiving (1) probiotic and zinc, (2) probiotic and placebo, (3) placebo and zinc, (4) two placebos. Seroconversion showed a modest improvement among infants receiving probiotic (difference between groups 1, 2 and 3, 4 was 7.5% (97.5% Confidence Interval (CI): −1.4%, 16.2%), p = 0.066) but not zinc (difference between groups 1, 3 and 2, 4 was 4.4% (97.5% CI: −4.4%, 13.2%), p = 0.272). 16 serious adverse events were recorded, none related to study interventions.ConclusionsZinc or probiotic supplementation did not significantly improve the low immunogenicity of rotavirus vaccine given to infants in a poor urban community in India. A modest effect of combined supplementation deserves further investigation.Trial registrationThe trial was registered in India (CTRI/2012/05/002677).     

Rapid impact of rotavirus vaccine introduction to the National Immunization Plan in Southern Israel: Comparison between 2 distinct populations

BackgroundRotavirus vaccines were licensed in Israel in 2007, and in 2011 the pentavalent-vaccine (RV5) was introduced into the Israeli National Immunization plan.AimTo determine the effect of rotavirus-vaccines on the incidence of hospital visits due to rotavirus gastroenteritis (RVGE) and all-cause diarrhea in Jewish and Bedouin children <5 year residing in southern Israel.MethodsWe conducted a population-based, prospective, observational study. Data from 2006 through 2013 were analyzed. Our hospital is the only medical center in the region, enabling age-specific incidences calculation.ResultsIn the pre-vaccine period, the overall RVGE hospital visits rates per 1000 in children <12, 12–23 and 24–59 m were 16.1, 18.6 and 1.4 in Jewish children, respectively. The respective rates in Bedouin children were 26.4, 12.5 and 0.7 (P < 0.001 for <12 m).Hospitalization rates were higher among Bedouin than among Jewish children (60.0% vs. 39.7%, P < 0.001). Vaccine uptake was faster in the Jewish vs. the Bedouin population.In the year following RV5 introduction, RVGE hospital visits rates declined by 82%, 70% (P < 0.001 both) and 36% (P = 0.092) in Jewish children <12, 12–23 and 24–59 m, respectively. In Bedouin children, the respective RVGE rates declined by 70% (P < 0.001), 21% (P = ns) and 14% (P = ns).Throughout the study, RVGE rates declined significantly in children <12, and 12–23 m by 80% and 88% in Jewish children, respectively, and by 62 and 75% in Bedouin children, respectively (P < 0.001 for all declines). In children 24–59 m, RVGE rates declined by 46% (P = 0.025) in Jewish children, but no reduction was observed in Bedouin children. The dynamics of all-cause diarrhea rates were similar to that of RVGE.ConclusionsSignificant reductions of RVGE rates were observed, following Rota-vaccine introduction in southern Israel in both Jewish and Bedouin children. However, the impact was faster and more profound in Jewish children, probably related to higher vaccine uptake and possibly to lifestyle differences.     

Evaluating the first introduction of rotavirus vaccine in Thailand: Moving from evidence to policy

BackgroundWe assessed the effectiveness and possible impact of introducing rotavirus vaccine into the routine immunization program.MethodsTwo provinces were selected for an observational study, one where vaccine was introduced and another where vaccine was not available. In these areas, two sub-studies were linked. The prospective cohort study enrolled children 2 month old and followed them to the age of 18 months to detect all diarrhea episodes. The hospital surveillance study enrolled all children up to age 5 hospitalized with diarrhea whose fecal samples were tested for rotavirus. Rates of rotavirus hospitalizations in older children who had not been vaccinated in both settings provided data to determine whether immunization had an indirect herd effect. The key endpoints for the study were both vaccine effectiveness (VE) based upon hospitalized rotavirus diarrhea and herd protection.FindingsFrom the cohort study, the overall VE for hospitalized rotavirus diarrhea was 88% (95%CI 76–94). Data from hospital surveillance indicated that for 2 consecutive years, the seasonal peak of rotavirus admissions was no longer present in the vaccinated area. Herd protection was observed among older children born before the rotavirus vaccine program was introduced, who experienced a 40–69% reduction in admission for rotavirus.ConclusionsRotavirus vaccine was highly effective in preventing diarrheal hospitalizations and in conferring herd protection among older children who had not been vaccinated.     

Disease burden of enterovirus infection in Taiwan: Implications for vaccination policy

ObjectivesThis study aimed to assess the disease burden and economic impacts of human nonpolio enteroviruses (NPEV) and enterovirus A71 (EV-A71) infection in Taiwan.Materials and methodsWe included children under five years old (n = 983,127–1,118,649) with ICD-9-CM codes 0740 (herpangina) or 0743 (hand-foot-and-mouth disease) from the 2006 to 2010 National Health Insurance Database. Severity of enterovirus infection was assessed from outpatient/emergency visits, hospitalization (with/without intensive care unit [ICU] admission), infection with severe complications, and death. We estimated medical costs and indirect costs from the societal perspective.ResultsThe annual rates of NPEV events for children under five years old ranged from 13.9% to 38.4%, of which 5.1–8.8% were hospitalized. EV-A71 accounted for 7.8% of all NPEV medical costs, but 79.1% of NPEV ICU costs. Travel costs and productivity loss of caregivers were $37.1 (range: $24.5–$64.7) million per year. These costs were not higher in the EV-A71 dominant year ($34.4 million) compared with those in the other years. Productivity losses resulting from premature mortality by NPEV infection were $0.8 (range: $0.0–$2.9) million per year, of which 96.3% were caused by EV-A71.ConclusionsDiseases associated with NPEV other than EV-A71 were responsible for most of the medical expenses. In addition, caregiver productivity loss by high rates of NPEV infection impacted the society much more than medical costs. A multi-valent vaccine that includes EV-A71 and other serotypes, for example coxsackievirus A16, may be beneficial to the health of children in Taiwan.     

Impact of rotavirus vaccine on all-cause diarrhea and rotavirus hospitalizations in Madagascar

BackgroundRotavirus vaccine was introduced into the Extended Program on Immunization in Madagascar in May 2014. We analyzed trends in prevalence of all cause diarrhea and rotavirus hospitalization in children <5 years of age before and after vaccine introduction and assessed trend of circulating rotavirus genotypes at Centre Hospitalier Universitaire Mère Enfant Tsaralalàna (CHU MET).MethodsFrom January 2010 to December 2016, we reviewed the admission logbook to observe the rate of hospitalization caused by gastroenteritis among 19619 children <5 years of age admitted at the hospital. In June 2013–December 2016, active rotavirus surveillance was also conducted at CHUMET with support from WHO. Rotavirus antigen was detected by EIA from stool specimen of children who are eligible for rotavirus gastroenteritis surveillance at sentinel site laboratory and rotavirus positive specimens were further genotyped at Regional Reference Laboratory by RT-PCR.ResultsDiarrhea hospitalizations decreased after rotavirus vaccine introduction. The median proportion of annual hospitalizations due to diarrhea was 26% (range: 31–22%) before vaccine introduction; the proportion was 25% the year of vaccine introduction, 17% in 2015 and 16% in 2016. Rotavirus positivity paralleled patterns observed in diarrhea. Before vaccine introduction, 56% of stool specimens tested positive for rotavirus; the percent positive was 13% in 2015, 12% in 2016. Diverse genotypes were detected in the pre-vaccine period; the most common were G3P[8] (n = 53; 66%), G2P[4] (n = 12; 15%), and G1P[8] (n = 11; 14%). 6 distinct genotypes were found in 2015; the most common genotype was G2P[4] (n = 10; 67%), the remaining, 5, G12[P8], G3[P8], G1G3[P4], G3G12[P4][P8] and G1G3[NT] had one positive specimen each.ConclusionsFollowing rotavirus vaccine introduction all-cause diarrhea and rotavirus-specific hospitalizations declined dramatically. The most common genotypes detected in the pre-vaccine period were G3P[8] and G2P[4] in 2015, the post vaccine period.     

Association between mixed rotavirus vaccination types of infants and rotavirus acute gastroenteritis

IntroductionRotavirus remains the leading cause of severe diarrhea in children under 5 years worldwide. In the US, Rotarix^® (RV1) and RotaTeq^® (RV5), have been associated with reductions in and severity of rotavirus disease. Studies have evaluated the impact of RV1 or RV5 but little is known about the impact of incomplete or mixed vaccination upon vaccine effectiveness.MethodsCase control study to examine association of combined RV1 and RV5 and rotavirus acute gastroenteritis, factoring severity of diarrheal disease. Children born after March 1, 2009 with acute gastroenteritis from three pediatric hospitals in Atlanta, Georgia were approached for enrollment. Survey was administered, stool specimen was collected, and vaccination records were obtained.Results891 of 1127 children with acute gastroenteritis were enrolled. Stool specimens were collected from 708 for rotavirus testing; 215 stool samples tested positively for rotavirus. Children >12 months of age were more likely to have rotavirus. Children categorized with Vesikari score of >11 were almost twice as likely to be rotavirus positive. Prior rotavirus vaccination decreased the mean Vesikari score, p < 0.0001. Children with complete single type vaccination were protected against rotavirus (OR 0.21, 95% CI: 0.14–0.31, p < 0.0001).ConclusionComplete rotavirus vaccination with a single vaccine type resulted in protection against rotavirus diarrhea and decrease in severity of rotavirus gastroenteritis. Incomplete rotavirus vaccination either with a single vaccine or mixed vaccination types also provided some protection.     

A randomized trial of rotavirus vaccine versus sucrose solution for vaccine injection pain

ObjectiveSucrose solutions are analgesic in infants. Oral rotavirus vaccine contains sucrose, however, it is not known if it possesses analgesic properties. The objective was to compare the analgesic effectiveness of rotavirus vaccine to sucrose solution when administered prior to injectable vaccines.MethodsInfants 2–4 months of age receiving oral rotavirus vaccine and two separate injectable vaccines on the same day were randomized to rotavirus vaccine (Rotarix™) first followed by the injectable vaccines and sucrose (Tootsweet™) afterwards, or vice versa. Pain was assessed by blinded raters using the Numerical Rating Scale (NRS, range 0–10) (parents, clinicians), or Modified Behavioural Pain Scale (MBPS, range 0–10) and cry duration (observers). Data were analyzed using t-tests or χ²-tests; Bonferroni correction was applied to correct for multiple comparisons, as appropriate.ResultsAltogether, 120 infants participated: 60 were randomized to rotavirus vaccine first. Groups did not differ in demographics, including; age (p = 0.448) and sex (p = 0.464). The mean pain score (standard deviation) for both vaccine injections did not differ between infants given rotavirus vaccine first versus sucrose solution first: observer MBPS, parent NRS and clinician NRS scores were 7.4 (1.6) vs. 7.7 (1.6), 4.9 (2.1) vs. 5.8 (2.1), and 4.2 (2.1) vs. 4.6 (2.2), respectively. Similarly, there was no difference between groups in cry duration.ConclusionRotavirus vaccine did not differ from sucrose solution in reducing injection-induced pain. Based on the findings, it is recommended that rotavirus vaccine be administered prior to injectable vaccines in infants aged 2 and 4 months.     

Comparison of whole-cell versus acellular pertussis vaccine effectiveness in school clusters of pertussis,France, 2013

Objectives and methodWe conducted a prospective study in 2013 to compare the whole-cell versus acellular pertussis vaccines effectiveness and duration of protection, following the occurrence of pertussis clusters.ResultsDuring seven school outbreaks, we identified 102 clinical pertussis cases, including 10 cases biologically confirmed by Bordetella pertussis specific PCR, among a cohort of 305 children in 2nd to 6th grade. The risk of pertussis when vaccinated with an acellular vaccine alone was 1.6 (RR = 1.6; 95% CI = 1.1–2.5) times higher than when vaccinated with a whole-cell vaccine or using a combined schedule.ConclusionsThe limited duration of protection conferred by the acellular vaccine reinforces the 2013 introduction of the pertussis booster at six years old.     

Replication-defective lymphocytic choriomeningitis virus vectors expressing guinea pig cytomegalovirus gB and pp65 homologs are protective against congenital guinea pig cytomegalovirus infection

BackgroundCongenital cytomegalovirus infection can be life-threatening and often results in significant developmental deficits and/or hearing loss. Thus, there is a critical need for an effective anti-CMV vaccine.ObjectiveTo determine the efficacy of replication-defective lymphocytic choriomeningitis virus (rLCMV) vectors expressing the guinea pig CMV (GPCMV) antigens, gB and pp65, in the guinea pig model of congenital CMV infection.MethodsFemale Hartley strain guinea pigs were divided into three groups: Buffer control group (n = 9), rLCMV-gB group (n = 11), and rLCMV-pp65 (n = 11). The vaccines were administered three times IM at 1.54 × 10⁶ FFU per dose at 21-day intervals. At two weeks after vaccination, the female guinea pigs underwent breeding. Pregnant guinea pigs were challenged SQ at ∼45–55 days of gestation with 1 × 10⁵ PFU of GPCMV. Viremia in the dams, pup survival, weights of pups at delivery, and viral load in both dam and pup tissues were determined.ResultsPup survival was significantly increased in the LCMV-gB vaccine group. There was 23% pup mortality in the gB vaccine group (p = 0.044) and 26% pup mortality in the pp65 vaccine group (p = 0.054) compared to 49% control pup mortality. The gB vaccine induced high levels of gB binding and detectable neutralizing antibodies, reduced dam viremia, and significantly reduced viral load in dam tissues compared to control dams (p < 0.03). Reduced viral load and transmission in pups born to gB-vaccinated dams was observed compared to pups from pp65-vaccinated or control dams.ConclusionsThe rLCMV-gB vaccine significantly improved pup survival and also increased pup weights and gestation time. The gB vaccine was also more effective at decreasing viral load in dams and pups and limiting congenital transmission. Thus, rLCMV vectors that express CMV antigens may be an effective vaccine strategy for congenital CMV infection.     

Temporal association of rotavirus vaccination and genotype circulation in South Africa: Observations from 2002 to 2014

BackgroundRotavirus vaccination has reduced diarrhoeal morbidity and mortality globally. The monovalent rotavirus vaccine was introduced into the public immunization program in South Africa (SA) in 2009 and led to approximately 50% reduction in rotavirus hospitalization in young children. The aim of this study was to investigate the rotavirus genotype distribution in SA before and after vaccine introduction.Materials and methodsIn addition to pre-vaccine era surveillance conducted from 2002 to 2008 at Dr George Mukhari Hospital (DGM), rotavirus surveillance among children <5 years hospitalized for acute diarrhoea was established at seven sentinel sites in SA from April 2009 to December 2014. Stool specimens were screened by enzyme immunoassay and rotavirus positive specimens genotyped using standardised methods.ResultsAt DGM, there was a significant decrease in G1 strains from pre-vaccine introduction (34%; 479/1418; 2002–2009) compared to post-vaccine introduction (22%; 37/170; 2010–2014; p for trend <.001). Similarly, there was a significant increase in non-G1P[8] strains at this site (p for trend <.001). In expanded sentinel surveillance, when adjusted for age and site, the odds of rotavirus detection in hospitalized children with diarrhoea declined significantly from 2009 (46%; 423/917) to 2014 (22%; 205/939; p < .001). The odds of G1 detection declined significantly from 2009 (53%; 224/421) to 2010–2011 (26%; 183/703; aOR = 0.5; p < .001) and 2012–2014 (9%; 80/905; aOR = 0.1; p < .001). Non-G1P[8] strains showed a significant increase from 2009 (33%; 139/421) to 2012–2014 (52%; 473/905; aOR = 2.5; p < .001).ConclusionsRotavirus vaccination of children was associated with temporal changes in circulating genotypes. Despite these temporal changes in circulating genotypes, the overall reduction in rotavirus disease in South Africa remains significant.     

Zinc supplementation fails to increase the immunogenicity of oral poliovirus vaccine: A randomized controlled trial

BackgroundPolio eradication remains a challenge in Pakistan and the causes for the failure to eradicate poliomyelitis are complex. Undernutrition and micronutrient deficiencies, especially zinc deficiency, are major public health problems in Pakistan and could potentially affect the response to enteric vaccines, including oral poliovirus vaccine (OPV).ObjectiveTo assess the impact of zinc supplementation among infants on immune response to oral poliovirus vaccine (OPV).MethodsA double-blind, randomized placebo-controlled trial was conducted in newborns (aged 0–14 days). Subjects were assigned to either receive 10 mg of zinc or placebo supplementation daily for 18 weeks. Both groups received OPV doses at birth, at 6 weeks, 10 weeks and 14 weeks. Data was collected on prior immunization status, diarrheal episodes, breastfeeding practices and anthropometric measurements at recruitment and at 6 and 18 weeks. Blood samples were similarly collected to determine the antibody response to OPV and for micronutrient analysis. Logistic regression was used to determine the relationship between seroconversion and zinc status.ResultsOverall, 404 subjects were recruited. At recruitment, seropositivity was already high for poliovirus (PV) serotype 1 (zinc: 91.1%; control: 90.5%) and PV2 (90.0%; 92.7%), with lower estimates for PV3 (70.0%; 64.8%). By week 18, the proportion of subjects with measured zinc levels in the normal range (i.e. ≥60 μg/dL) was significantly greater in the intervention group compared to the control group (71.9%; 27.4%; p < 0.001). No significant difference in seroconversion was demonstrated between the groups for PV1, PV2, or PV3.ConclusionsThere was no effect of zinc supplementation on OPV immunogenicity. These conclusions were confirmed when restricting the analysis to those with measured higher zinc levels.     

Breastfeeding linked to the reduction of both rotavirus shedding and IgA levels after Rotarix® immunization in Mexican infants

We examined potential risk factors on vaccine virus shedding and antibody seroresponse to human rotavirus vaccine (Rotarix) in Mexican infants. Two doses of Rotarix were administered to infants during the first two visits for their routine childhood immunization (∼8 and 15 weeks of age) in Mexico City. Infant’s characteristics and socioeconomic indicators were obtained, including history of long-term feeding practices (exclusively/predominantly breastfed and exclusively/predominantly non-breastfed). Two serum specimens were collected, one during the second rotavirus vaccine visit and one 7 weeks later. Stool specimens were collected between days 4–7 after each of the two rotavirus vaccine doses. Rotavirus IgA and IgG titers in serum were determined by enzyme immunoassays (EIA) and rotavirus shedding in stool was assessed by EIA and confirmed by RT-PCR.The overall rotavirus IgA geometric mean titers (GMT) increased significantly post dose 2 from post dose 1 [176 (95%CI: 113–273) to 335 (238–471); p = 0.020). Infants who were exclusively/predominantly breastfed were less likely to shed vaccine virus in stool than those who were formula-fed (22% vs. 43%, p = 0.016). Infants who were breastfed had lower rotavirus IgA titers than those who were formula-fed after dose 1 [GMT: 145 (84–250) vs. 267 (126–566) p = 0.188] and dose 2 [236 (147–378) vs.578 (367–910), p = 0.007]. Infants who shed vaccine virus post dose 1 had significantly higher serum IgA GMT than those who did not shed [425 (188–965) vs. 150 (84–266), p = 0.038]. Breastfeeding was linked with the reduction of both stool vaccine shedding, and IgA seroresponse. The reduced rotavirus replication in the gut and shedding after dose 1 may explain in part the lower IgA response in serum.     

Seropositivity to non-vaccine incorporated genotypes induced by the bivalent and quadrivalent HPV vaccines: A systematic review and meta-analysis

BackgroundHuman papillomavirus vaccines have demonstrated remarkable efficacy against persistent infection and disease associated with vaccine-incorporated genotypes and a degree of efficacy against some genetically related, non-vaccine-incorporated genotypes. The vaccines differ in the extent of cross-protection against these non-vaccine genotypes. Data supporting the role for neutralizing antibodies as a correlate or surrogate of cross-protection are lacking, as is a robust assessment of the seroconversion rates against these non-vaccine genotypes.MethodsWe performed a systematic review and meta-analysis of available data on vaccine-induced neutralizing antibody seropositivity to non-vaccine incorporated HPV genotypes.ResultsOf 304 articles screened, 9 were included in the analysis representing ca. 700 individuals. The pooled estimate for seropositivity against HPV31 for the bivalent vaccine (86%; 95%CI 78–91%) was higher than that for the quadrivalent vaccine (61%; 39–79%; p = 0.011). The pooled estimate for seropositivity against HPV45 for the bivalent vaccine (50%; 37–64%) was also higher than that for the quadrivalent vaccine (16%; 6–36%; p = 0.007). Seropositivity against HPV33, HPV52 and HPV58 were similar between the vaccines. Mean seropositivity rates across non-vaccine genotypes were positively associated with the corresponding vaccine efficacy data reported from vaccine trials.ConclusionsThese data improve our understanding of vaccine-induced functional antibody specificity against non-vaccine incorporated genotypes and may help to parameterize vaccine-impact models and improve patient management in a post-vaccine setting.     

HPV vaccine acceptance among adolescent males and their parents in two suburban pediatric practices

PurposeTo measure HPV vaccine acceptance among unvaccinated adolescent males and parents and correlate acceptance with knowledge, awareness, and personal experience.MethodsAdolescent males ages 11–21 years old and their parents completed questionnaires measuring attitudes and knowledge about HPV vaccination and personal experience. Acceptance was defined as wanting the vaccine and conditional acceptance as wanting the vaccine if it would protect against genital warts or cervical cancer.ResultsAdolescent (n = 154) and parent (n = 121) vaccine acceptance was low (16% and 34%, respectively); however, conditional acceptance was higher. While adolescents had similar conditional acceptance for a vaccine against genital warts and cervical cancer, parents reported higher conditional acceptance for protection against genital warts. Independent predictors of acceptance included personal experience and demographic variables.ConclusionsHPV vaccine acceptance among adolescents and parents was low. Conditional acceptance levels highlight the importance of education about a few important benefits of HPV vaccination, which may increase vaccination rates.     

A study of different buffers to maximize viability of an oral Shigella vaccine

Live, whole cell killed and subunit vaccines are being developed for diarrheal diseases caused by V. cholerae, Shigella species, ETEC, and Campylobacter. Some of these vaccines can be administered orally since this route best mimics natural infection. Live vaccines administered orally have to be protected from the harsh acidic gastric environment. Milk and bicarbonate solutions have been administered to neutralize the stomach acid. For many Shigella vaccine trials, 100–120 ml of a bicarbonate solution is ingested followed by the live vaccine candidate, which is delivered in 30 ml of bicarbonate, water or saline. It is not clear if maximum bacterial viability is achieved under these conditions. Also, volumes of neutralizing buffer that are optimal for adults may be unsuitable for children and infants. To address these questions, we performed studies to determine the viability and stability of a Shigella sonnei vaccine candidate, WRSS1, in a mixture of different volumes of five different buffer solutions added to hydrochloric acid to simulate gastric acidity. Among the buffers tested, bicarbonate solution, rotavirus buffer and CeraVacx were better at neutralizing acid and maintaining the viability of WRSS1. Also, a much smaller volume of the neutralizing buffer was sufficient to counteract stomach acid while maintaining bacterial viability.     

Exploring evidence for behavioral risk compensation among participants in an HIV vaccine clinical trial

BackgroundHIV vaccine trial participants may engage in behavioral risk compensation due to a false sense of protection. We conducted an ancillary study of an HIV Vaccine Trials Network (HVTN) vaccine efficacy trial to explore risk compensation among trial participants compared to persons who were willing to participate but ineligible based on previous exposure to the Ad5 virus (Ad5+) across three timepoints.MethodsParticipants were drawn from the Atlanta, GA site of the HVTN 505 vaccine trial. From 2011–2013, all persons who met prescreening criteria for the clinical trial and presented for Ad5 antibody testing were invited to participate in the ancillary study. Data were collected from vaccine trial participants (n = 51) and Ad5+ participants (n = 60) via online surveys across three timepoints: baseline, T2 (after trial participants received 2/4 injections) and T3 (after trial participants received 4/4 injections). Data analyses assessed demographic, psychosocial, and behavioral differences at baseline and changes at each timepoint.ResultsAt baseline, Ad5+ participants were less likely to have some college education (p = 0.024) or health insurance (p = 0.008), and were more likely to want to participate in the vaccine trial “to feel safer having unprotected sex” (p = 0.005). Among vaccine trial participants, unprotected anal sex with a casual partner (p = 0.05), HIV transmission worry (p = 0.033), and perceived chance of getting HIV (p = 0.027), decreased across timepoints.ConclusionsStudy findings suggest that persons with previous exposure to Ad5 may be systematically different from their Ad5-negative peers. Unprotected anal sex with a casual partner significantly decreased among HIV vaccine trial participants, as did HIV worry and perceived chance of getting HIV. Findings did not support evidence of risk compensation among HIV vaccine trial participants compared to Ad5+ participants.     

Immunogenicity and safety of an E. coli-produced bivalent human papillomavirus (type 16 and 18) vaccine: A randomized controlled phase 2 clinical trial

BackgroundThis study aimed to investigate the dosage, immunogenicity and safety profile of a novel human papillomavirus (HPV) types 16 and 18 bivalent vaccine produced by E. coli.MethodsThis randomized, double-blinded, controlled phase 2 trial enrolled women aged 18–25 years in China. Totally 1600 eligible participants were randomized to receive 90 μg, 60 μg, or 30 μg of the recombinant HPV 16/18 bivalent vaccine or the control hepatitis B vaccine on a 0, 1 and 6 month schedule. The designated doses are the combined micrograms of HPV16 and 18 VLPs with dose ratio of 2:1. The immunogenicity of the vaccines was assessed by measuring anti-HPV 16 and 18 neutralizing antibodies and total IgG antibodies. Safety of the vaccine was assessed.ResultsAll but one of the seronegative participants who received 3 doses of the HPV vaccines seroconverted at month 7 for anti-HPV 16/18 neutralizing antibodies and IgG antibodies. For HPV 16, the geometric mean titers (GMTs) of the neutralizing antibodies were similar between the 60 μg (GMT = 10,548) and 90 μg (GMT = 12,505) HPV vaccine groups and were significantly higher than those in the 30 μg (GMT = 7596) group. For HPV 18, the GMTs of the neutralizing antibodies were similar among the 3 groups. The HPV vaccine was well tolerated. No vaccine-associated serious adverse events were identified.ConclusionThe prokaryotic-expressed HPV vaccine is safe and immunogenic in women aged 18–25 years. The 60 μg dosage formulation was selected for further investigation for efficacy.Clinical trials registration: NCT01356823.