What predicts postpartum pertussis booster vaccination? A controlled intervention trial

Background‘Cocooning’ aims to protect susceptible infants from pertussis via caregiver vaccination. Control trials evaluating educational interventions to promote cocooning are lacking. We evaluated the role of message-framing vs. standard health information in promoting pertussis vaccination.MethodsWe recruited postpartum women from a maternity hospital in Sydney, Australia (November 2010–July 2012). Participants self-completed a pertussis knowledge and attitudes questionnaire. We then assigned pertussis-susceptible (no pertussis vaccine ≤10 years) participants to receive a gain-framed, loss-framed pamphlet or control (Government Pertussis factsheet) using weekly sequential block allocation. Next, participants were offered a pertussis vaccine (dTpa) and completed a post-questionnaire on discharge.ResultsA baseline questionnaire was completed for 96.4% (1433/1486) of postpartum women approached. Missing data was excluded (n = 29). Next, participants (1404) were screened for vaccine status: 324 (23%) reported prior pertussis booster vaccine receipt, leaving 1080 participants requiring vaccination. Among susceptible mothers, 70% (754/1080) were vaccinated post-intervention. Rates were similar between ‘gain’, ‘loss’ or ‘control’ pamphlets (69.1% vs. 71.8% vs. 68.8%; p = 0.62). Intention to be vaccinated (OR 2.46, p < 0.001; 95% CI: 1.69–3.58), perceived vaccine benefits (OR: 1.61, p < 0.001; 95% CI: 1.25–2.15) and having received a vaccine recommendation (OR 1.68; p = 0.025; 95% CI: 1.07–2.65) were independent predictors of vaccine uptake. At discharge, overall pertussis vaccine coverage had increased from 23% to 77% among women screened (1078/1404).ConclusionA cocooning strategy for pertussis vaccination can be highly effective when partially implemented within maternity hospitals, with information accompanied by a funded vaccine. Mothers were highly receptive to vaccination in the postnatal ward: facts about pertussis were as effective as message-framing in promoting a high uptake of 70%. Perceived vaccine benefits, intentions and vaccine recommendation were important predictors of uptake. Our intervention trial increased the existing pertussis vaccine coverage of 23–77%.     

Vaccine effectiveness of tetanus toxoid,reduced diphtheria toxoid,and acellular pertussis vaccine during a pertussis outbreak in Maine

BackgroundMultiple school-associated pertussis outbreaks were reported in Maine from 2010 to 2011. These outbreaks were associated with an overall increase in pertussis cases statewide. Waning of protection in students recently vaccinated with tetanus, diphtheria, and acellular pertussis (Tdap) has been implicated in the increase in reported rates of pertussis nationally.MethodsWe conducted a retrospective cohort study to evaluate Tdap vaccine effectiveness (VE) among students aged 11–19 years in two schools reporting outbreaks in 2011. All pertussis cases reported from August through November, 2011 at the two schools were included. Vaccination history was verified using provider information, state vaccine registry data, and parental verification. Attack rates (AR) were calculated. VE and duration of protection was calculated as VE = 1 − (AR_vaccinated/AR_unvaccinated) × 100% using a log binomial regression model.ResultsOf 416 students enrolled, 314 were included in the analyses. Twenty-nine cases collectively in Schools A and B. Tdap coverage was 65% at School A and 42% at School B before the start of the outbreak. Among students enrolled in the study, attack rates were 11.9% and 7.7% at Schools A and B, respectively. Overall VE was 68.5% (95% confidence interval (CI) 37.7–86.2). VE was 70.4% (95% CI 17.5–89.4) for School A and 65.2% (95% CI −19.2 to 89.9) for School B. VE <2 years versus ≥2 years from outbreak onset was not significantly different.ConclusionsTdap was moderately effective in preventing disease among vaccinated students. Vaccine coverage of 65% or less was suboptimal and might contribute to outbreaks. Waning VE was not demonstrated. Increased vaccination coverage rates as well as further evaluation of the role of acellular vaccine on VE is needed.     

Age-specific effectiveness following each dose of acellular pertussis vaccine among infants and children in New Zealand

BackgroundThough it is believed the switch from whole cell to acellular pertussis vaccine has contributed to the resurgence of pertussis disease, few studies have evaluated vaccine effectiveness (VE) and duration of protection provided by an acellular vaccine schedule including three primary doses but no toddler-age dose. We assessed this schedule in New Zealand (NZ), a setting with historically high rates of pertussis disease, and low but recently improved immunisation coverage. We further evaluated protection following the preschool-age booster dose.MethodsWe performed a nested case-control study using national-level healthcare data. Hospitalised and non-hospitalised pertussis was detected among children 6 weeks to 7 years of age between January 2006 and December 2013. The NZ National Immunisation Register provided vaccination status for cases and controls. Conditional logistic regression was used to calculate dose-specific VE with duration of immunity examined by stratifying VE into ages aligned with the immunisation schedule.ResultsVE against pertussis hospitalisation was 93% (95% confidence interval [CI]: 87, 96) following three doses among infants aged 5–11 months who received three compared to zero doses. This protection was sustained through children’s fourth birthdays (VE ⩾ 91%). VE against non-hospitalised pertussis was also sustained after three doses, from 86% (95% CI: 80, 90) among 5–11 month olds to 84% (95% CI: 80, 88) among 3-year-olds. Following the first booster dose at 4 years of age, the protective VE of 93% (95% CI: 90, 95) among 4-year-olds continued through 7 years of age (VE ⩾ 91%).ConclusionsWe found a high level of protection with no reduction in VE following both the primary course and the first booster dose. These findings support a 3-dose primary course of acellular vaccine with no booster dose until 4 years of age.     

Risk factors of ICU or high dependency requirements amongst hospitalized pediatric pertussis cases: A 10 year retrospective series,Singapore

IntroductionPertussis causes the highest complication rates and deaths in the infant group. Our study explored risk factors for ICU/high dependency (HD) admissions and intubation/non-invasive ventilation (NIV).MethodsA retrospective review of pertussis admissions over 10 years from 2007 to 2016 was done at KK Women's and Children's Hospital, Singapore. To understand risk factors for severe pertussis infection, we compared cases requiring ICU/HD care with controls admitted to the general ward. Risk factors for intubation/NIV were also studied. Vaccine efficacy for protection against ICU/HD admission or intubation/NIV was also calculated.ResultsThere were 200 pertussis patients with a median age of 2.75 months. Sixty-one % were ≤3 months and 14.5% were <6 weeks old. Majority of patients (77%) had no prior pertussis vaccination. After removing 3 patients with missing vaccination records, 20 cases were compared with 177 controls. On univariate analysis, risk factors for ICU/HD admission comprised: Age ≤3 months, contact history, underlying co-morbidity, prematurity, absent DTaP vaccination, lymphocytosis, hyperleukocytosis (wbc ≥50 × 10⁹/L), thrombocytosis (platelet ≥500 × 10⁹/L), and pneumonia. Multivariate analysis revealed that age ≤3 months (OR 40, 95% CI 4.57–1111.11, p = .007), co-morbidity (OR 8.46 (95% CI 1.47–56.89, p = .019), pneumonia (OR 18.08, 95% CI 3.22–132.15, p = .002), white cell count (OR 1.07, 95% CI 1.01–1.14, p = .023) and cyanosis (OR 5.09, 95% CI 1.31–24.71, p = .026) were risk factors for ICU/HD admission. Prior DTaP vaccination had a vaccine effectiveness of 86.5% in preventing ICU/HD admission and 82.1% in preventing intubation/NIV.ConclusionsAs the majority of pertussis patients were infants ≤3 months old who are at high risk for ICU/HD admission and intubation/NIV, prevention is key to reducing pertussis morbidity. Even though not statistically significant, DTaP vaccination had a role in preventing ICU/HD admission and intubation/NIV.     

Negative impact of prior influenza vaccination on current influenza vaccination among people infected and not infected in prior season: A test-negative case-control study in Japan

BackgroundAccumulating evidences indicate that repeated influenza vaccination has negative impact on the vaccine effectiveness (VE). However no published studies considered past influenza infection when assessing the VE of repeated vaccination.MethodsProspective surveillance was conducted from 2009 to 2012 at a community hospital on a small island in Japan. The study included all outpatients with an influenza-like illness (ILI) who attended the hospital, and a rapid diagnostic test (RDT) was used to diagnose influenza A/B infection. The VE of trivalent inactivated influenza vaccine (TIV) against medically attended influenza A (MA-fluA) was estimated using a test-negative case-control study design. The influence of TIV in the prior season on VE in the current season was investigated in the context of MA-fluA during the prior season.ResultsDuring the three influenza seasons, 5838 ILI episodes (4127 subjects) were analysed. Subjects who had an episode of MA-fluA in the prior season were at a significantly lower risk of MA-fluA in the current season (adjusted odds ratio: 0.38, 95% CI: 0.30–0.50). The overall adjusted VE was 28% (95% CI, 14–40). VE was substantially lower in subjects vaccinated in the prior season compared to those who had not been vaccinated in prior season (19%; 95% CI: 0–35 vs 46%; 95% CI: 26–60, test for interaction, P value <0.05). In subjects who did not have MA-fluA in the prior season showed the attenuation of VE due to repeated vaccination (13%; 95% CI: −7 to 30 vs 44%; 95% CI: 24–59, test for interaction, P < 0.05). However this effect was not detected in subjects who had contracted MA-fluA in the prior season.ConclusionsNegative effects of repeated vaccination were significant among those without history of MA-fluA in the prior season.     

Vaccine effectiveness of PCV13 in a 3 + 1 vaccination schedule

ObjectiveTo assess the vaccine effectiveness (VE) of PCV13 for invasive pneumococcal disease (IPD) regarding the extra six serotypes with a 3 + 1 schedule in Germany.MethodsActive surveillance for IPD in children <16 years eligible for PCV13 vaccination. We used the Broome method and logistic regression to estimate VE.ResultsData on 164/304 reported IPD cases were informative and met the inclusion criteria. VE for the extra six serotypes was 88% [95% confidence interval (CI): 73; 95] and 83% [56; 94] for at least one and for at least two doses respectively. VE for the complete 3 + 1 vaccination schedule was not conclusive because of a wide 95% CI. For serotype 3 VE appeared to be zero with an even wider 95% CI.ConclusionPCV13 VE against the extra six serotypes with the 3 + 1 schedule in Germany was only marginally higher compared to previously published data for the 2 + 1 schedule.     

Combined tetanus-diphtheria and pertussis vaccine during pregnancy: transfer of maternal pertussis antibodies to the newborn

Background and objectivesPertussis is currently an emerging public health concern in some countries with high vaccination coverage. It is expected that maternal pertussis immunization could provide newborn protection. We compared pertussis toxin antibody (anti-PT) levels in women during pregnancy (pre- and post-vaccination) with respect to levels in the newborn at delivery in women vaccinated during pregnancy. We also estimated anti-PT titers at primary infant vaccination.MethodsObservational study of pregnant women vaccinated with Tdap (≥20 weeks gestation) and their newborns between May 2012 and August 2013. Anti-PT levels were determined by ELISA in maternal (pre- and post-vaccination) and newborn blood.ResultsPre-vaccination, post-vaccination maternal and newborn samples were available in 132 subjects. Mean maternal age was 34.2 (SD 4.3) years. Median weeks of gestation at vaccination were 27.2 (Q1–Q3 21.7–30.8). Anti-PT (≥10 IU/ml) levels were found in 37.1% of maternal pre-vaccination samples (geometric mean titer (GMT) 7.9 IU/ml (95% CI 6.8–9.2)), 90.2% of post-vaccination samples (GMT 31.1 IU/ml (95% CI 26.6–36.3)) and 94.7% of newborns (GMT 37.8 IU/ml (95% CI 32.3–44.1)). The Lin concordance index between post-vaccination maternal and newborn samples was 0.8 (95% CI 0.8–0.9). Transplacental transfer ratio was 146.6%. At two months of age, 66% of newborns had estimated anti-PT levels ≥10 IU/ml.ConclusionsThere was a high correlation between anti-PT levels in mothers and newborns, with higher levels in newborns, which should be sufficient to provide protection against pertussis during the first months of life. Vaccination of pregnant women seems to be an immunogenic strategy to protect newborns until primary infant immunization.     

Trends in reasons for non-receipt of influenza vaccination during pregnancy in Georgia, 2004–2011

BackgroundConsiderable research has identified barriers to antenatal influenza vaccination, yet no research has explored temporal trends in reasons for non-receipt.PurposeTo examine trends in reasons for non-receipt of influenza vaccination during pregnancy.MethodsSerial cross-sectional analyses using 8 years of Georgia Pregnancy Risk Assessment Monitoring Survey (PRAMS) data were conducted. Weighted logistic regression was used to examine trends in the prevalence of citing reasons for non-receipt over time.ResultsBetween 2004 and 2011, 8300 women reported no influenza vaccination during or immediately before pregnancy. Proportions of women citing “doctor didn’t mention vaccination,” “in first trimester during influenza season,” and “not pregnant during influenza season” decreased significantly over time (Doctor didn’t mention: 48.0% vs. 27.1%, test for trend p < 0.001; in first trimester: 26.8% vs. 16.3%, test for trend p < 0.001; not influenza season: 24.2% vs. 12.7%, test for trend p = 0.001). Safety concerns increased over 2004 proportions in 2010 (concern about side effects for me: 40.2% vs. 28.5%, prevalence ratio (PR): 1.41, 95% confidence interval (CI): 1.16, 1.71; concern about harming my baby: 38.9% vs. 31.0%, PR = 1.26, 95% CI: 1.04, 1.53) and 2011 (concern about side effects for me: 39.0% vs. 28.5%, PR = 1.37, 95% CI: 1.13, 1.65; concern about harming my baby: 38.8% vs. 31.0%, PR = 1.25, 95% CI: 1.04, 1.50). Following the 2009/2010 H1N1 pandemic, more Hispanic women cited concern about vaccination harming their baby than other women; in 2011, their concern remained elevated relative to non-Hispanic white women (63% vs. 35%; adjusted PR = 1.79, 95% CI: 1.23, 2.61).ConclusionExamining trends in reasons for non-receipt of antenatal influenza vaccination can reflect successes related to vaccine promotion and areas for improvement. By highlighting differential impacts of the 2009/2010 H1N1 pandemic, we reveal opportunities for additional research on tailoring vaccine promotion efforts to specific types of women.     

Assessing determinants of the intention to accept a pertussis cocooning vaccination: A survey among Dutch parents

IntroductionPertussis cocooning is one of the strategies aiming to prevent the potential harm of pertussis in infants by vaccinating (among others) their parents. Several countries adopted this strategy, but uptake is a problem. Determinants of parental uptake are important in the design of an effective vaccination programme. Therefore, this study aims to assess parents’ intention to accept a pertussis cocooning vaccination and its determinants.MethodsA 98 item questionnaire was developed based on a theoretical framework, assessing parents’ intention to accept a pertussis cocooning vaccination and its personal and psychosocial determinants. In addition, beliefs underlying parents’ attitude towards pertussis cocooning vaccination were assessed. Both logistic and linear regression analysis were used to assess univariate and multivariate associations amongst study variables.ResultsParents returned 282 questionnaires. The majority of the parents (78%) reported a positive intention to accept a pertussis cocooning vaccination. Attitude (OR 6.6, p < .001), anticipated negative affect in response to non acceptance (OR 1.65, p < .001), anticipated negative affect in response to acceptance (OR 0.55, p .040) and decisional uncertainty (OR 0.52, p .002) were significantly associated with intention. General vaccination beliefs (β 0.58, p < .001), moral norm (β 0.22, p < .001), perceived susceptibility of pertussis in children (β 0.10, p.004), and efficacy outcome expectations (β 0.15, p.011) were significant correlates of attitude towards pertussis cocooning vaccination.ConclusionThe parental intention to accept a pertussis cocooning vaccination in this study is rather high. Targeting the identified determinants of parents’ acceptance in a pertussis cocooning vaccination programme is crucial to secure that intention is translated into actual vaccination uptake.     

Intention to accept pertussis vaccine among pregnant women in Karachi,Pakistan

BackgroundMaternal immunization against pertussis is a potential strategy to protect young infants from severe disease. We assessed factors associated with intention to accept pertussis vaccination among pregnant women in Karachi, Pakistan.MethodsWe conducted a cross-sectional survey between May and August 2013 in pregnant women who visited healthcare centers in urban slums of Karachi city. Women completed a survey examining socio-demographic factors, vaccination history, knowledge on pertussis disease, perception of vaccine recommendation sources, and potential influences on vaccine decision-making.ResultsOf the 283 participants, 259 (92%) provided their intention to either accept or decline pertussis vaccination. Eighty-three percent women were willing to accept the pertussis vaccine if offered during pregnancy. About half (53%) of the participants had ever heard of pertussis disease. Perceptions of pertussis vaccine efficacy, safety, and disease susceptibility were strongly associated with intention to accept pertussis vaccine (p < 0.01). Healthcare providers, Ministry of Health, and mass media were considered as highly reliable sources of vaccine recommendation and associated with intention to accept antenatal pertussis vaccination (p < 0.001). Healthcare provider recommendation was a common reason cited by respondents for pregnant women to accept antenatal pertussis vaccination (p = 0.0005). However, opinion of primary decision-makers in the family (husbands and in-laws) was a crucial reason cited by respondents for pregnant women to reject pertussis vaccination in pregnancy (p = 0.003).ConclusionAntenatal pertussis vaccination initiatives in South Asia should strongly consider inclusion of family members, healthcare providers, national health ministries, and mass media to help implement new vaccination programs.     

Should professionals caring for children be vaccinated? Community perspectives on health care and child care worker immunisation

ObjectiveSeveral immunisations including influenza and pertussis are specifically recommended for healthcare workers (HCW) and childcare workers (CCW). This study aimed to assess community attitudes to HCW and CCW immunisation recommendations for pertussis and seasonal influenza.MethodsA cross-sectional study was conducted by Computer Assisted Telephone Interviewing (CATI) from April to May 2011. Statistical analyses used data weighted to the South Australian population by probability of selection, age, gender and geographical location using benchmarks derived from the 2009 Census population figures.ResultsAlmost all respondents supported vaccination of HCWs and CCWs against pertussis and influenza. For pertussis, 95.3% agreed nurses, 94.9% agreed doctors and 94.7% agreed CCWs have an obligation to be vaccinated. For influenza, 91.4% agreed nurses, 90.7% agreed doctors and 89.9% agreed CCWs have an obligation to be vaccinated. We identified higher support for protection against pertussis compared to influenza for all three groups of workers (p < 0.001). There were higher concerns if CCWs compared to HCWs were not vaccinated against pertussis (OR = 2.78) and influenza (OR = 1.99). Young (18–30 years) and older age (60+ years) and lower educational attainment were predictors of support for HCWs and CCWs to be vaccinated against influenza. For pertussis, lower educational attainment was a predictor of support for HCWs immunisation.ConclusionsCommunity support for CCW and HCW immunisation is strong with CCW immunisation was considered a priority. Pertussis immunisation was considered a higher priority than influenza immunisation for HCWs and CCWs. CCW immunisation should be considered for inclusion in public health immunisation programmes.     

Effectiveness of adenovirus type 5 vectored and inactivated COVID-19 vaccines against symptomatic COVID-19, COVID-19 pneumonia,and severe COVID-19 caused by the B.1.617.2 (Delta) variant: Evidence from an outbreak in Yunnan,China, 2021

BackgroundIn partial response to the coronavirus disease 2019 (COVID-19) pandemic, countries around the world are conducting large-scale vaccination campaigns. Real-world estimates of vaccine effectiveness (VE) against the B.1.617.2 (Delta) variant are still limited. An outbreak in Ruili city of China provided an opportunity to evaluate VE against the Delta variant of two types of COVID-19 vaccines in use in China and globally – inactivated (CoronaVac and BBIBP-CorV) and adenovirus type 5 vectored (Convidecia) vaccines.MethodsWe estimated VE using a retrospective cohort study two months after the Ruili vaccination campaign (median: 63 days). Close contacts of infected people (Chinese nationality, 18 years and above) were included to assess VE against symptomatic Covid-19, COVID-19 pneumonia, and severe COVID-19. We calculated the relative risks (RR) of the outcomes for unvaccinated compared with fully vaccinated individuals. We used logistic regression analyses to estimate adjusted VEs, controlling for gender and age group (18–59 years and 60 years and over).We compared unvaccinated and fully vaccinated individuals on duration of RT-PCR positivity and Ct value.FindingsThere were 686 close contacts eligible for VE estimates. Adjusted VE of ad5-vectored vaccine was 61.5% (95% CI, 9.5–83.6) against symptomatic COVID-19, 67.9% (95%CI: 1.7–89.9) against pneumonia, and 100% (95%CI: 36.6–100) against severe/critical illness. For the two inactivated vaccines, combined VE was 74.6% (95% CI, 36.0–90.0) against symptomatic COVID-19, 76.7% (95% CI: 19.3–93.3) against pneumonia, and 100% (95% CI: 47.6–100) against severe/critical COVID-19. There were no statistically significant differences in VE between two inactivated vaccines for symptomatic COVID-19 and for pneumonia, nor were there statistically significant differences between inactivated and ad5-vectored VE in any of the three outcomes. The median durations of RT-PCR positivity were 17 days for fifteen people vaccinated with an inactivated vaccine, 18 days for forty-four people vaccinated with the Ad5 vectored vaccine, and 26 days for eleven unvaccinated individuals. InterpretationThese results provide reassuring evidence that the three vaccines are effective at preventing Delta-variant COVID-19 in short term following vaccination campaign, and are most effective at preventing more serious illness. The findings of reduced duration of RT-PCR positivity and length of hospital stay associated with full vaccination suggests potential saving of health-care system resources.     

Pertussis vaccination during pregnancy: Antibody persistence in infants

Maternal pertussis vaccination is associated with higher levels of pertussis antibodies at birth. We assessed the persistence of pertussis antibodies until primary vaccination in infants whose mothers received Tdap (tetanus, diphtheria, acellular pertussis) vaccine during pregnancy. Infants were born at the Hospital Clinic of Barcelona (Spain) in November 2014. Anti-PT IgG was determined by ELISA at delivery, between the first and second month of life, and estimated at 2 months of age. The study included 37 infants whose mothers received Tdap between 21 and 38 weeks of gestation. Infants presented a decline in GMC of anti-PT IgG between peripartum and follow-up levels, 52.7 (95% CI 34.7–80.2) versus 7.5 (95% CI 4.2–13.3) at 2 months of age (p < 0.001). The median half-life of maternal antibodies was 47 days. More than half (51.4%) the infants presented detectable anti-PT IgG before the start of primary infant vaccination.     

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.     

Validity of the estimates of oral cholera vaccine effectiveness derived from the test-negative design

BackgroundThe test-negative design (TND) has emerged as a simple method for evaluating vaccine effectiveness (VE). Its utility for evaluating oral cholera vaccine (OCV) effectiveness is unknown. We examined this method's validity in assessing OCV effectiveness by comparing the results of TND analyses with those of conventional cohort analyses.MethodsRandomized controlled trials of OCV were conducted in Matlab (Bangladesh) and Kolkata (India), and an observational cohort design was used in Zanzibar (Tanzania). For all three studies, VE using the TND was estimated from the odds ratio (OR) relating vaccination status to fecal test status (Vibrio cholerae O1 positive or negative) among diarrheal patients enrolled during surveillance (VE =  (1 − OR)×100%). In cohort analyses of these studies, we employed the Cox proportional hazard model for estimating VE (=1 − hazard ratio)×100%).ResultsOCV effectiveness estimates obtained using the TND (Matlab: 51%, 95% CI:37–62%; Kolkata: 67%, 95% CI:57–75%) were similar to the cohort analyses of these RCTs (Matlab: 52%, 95% CI:43–60% and Kolkata: 66%, 95% CI:55–74%). The TND VE estimate for the Zanzibar data was 94% (95% CI:84–98%) compared with 82% (95% CI:58–93%) in the cohort analysis. After adjusting for residual confounding in the cohort analysis of the Zanzibar study, using a bias indicator condition, we observed almost no difference in the two estimates.ConclusionOur findings suggest that the TND is a valid approach for evaluating OCV effectiveness in routine vaccination programs.     

Tetanus,diphtheria, and acellular pertussis vaccination during pregnancy and reduced risk of infant acute respiratory infections

BackgroundTo protect infants from pertussis infection, the Advisory Committee on Immunization Practices (ACIP) recommends women receive the tetanus toxoid, reduced diphtheria toxoid, acellular pertussis (Tdap) vaccine between 27 and 36 weeks of pregnancy. Here, we assessed the association between timing of maternal Tdap vaccination during pregnancy and acute respiratory infection (ARI) in infants <2 months of age.MethodsThis retrospective cohort study included 99,434 infants born to active duty military women in the Department of Defense Birth and Infant Health Registry from 2006 through 2013. Multivariable log-binomial regression was used to calculate relative risks (RRs) and 95% confidence intervals (CIs) for the association between maternal Tdap vaccination during pregnancy and infant ARI at <2 months of age.ResultsInfants of mothers who received Tdap vaccination during pregnancy vs those who did not were 9% less likely to be diagnosed with an ARI at <2 months of age (RR, 0.91; 95% CI, 0.84–0.99), and the risk was 17% lower if vaccination was received between 27 and 36 weeks of pregnancy (RR, 0.83; 95% CI, 0.74–0.93). Similar results were observed when comparing mothers who received Tdap vaccination prior to pregnancy in addition to Tdap vaccination between 27 and 36 weeks of pregnancy versus mothers who only received vaccination prior to pregnancy (RR, 0.85; 95% CI, 0.74–0.98).ConclusionsMaternal Tdap vaccination between 27 and 36 weeks of pregnancy was consistently protective against infant ARI in the first 2 months of life vs no vaccination during pregnancy, regardless of Tdap vaccination prior to pregnancy. Our findings strongly support current ACIP guidelines recommending Tdap vaccination in late pregnancy for every pregnancy.     

Evaluating the effectiveness of the universal immunization program against varicella in Japanese children

ObjectiveMatched case control study was conducted to elucidate the effectiveness of the Oka/Biken vaccine immediately after implementation of the universal immunization program in Japan.MethodsCases were laboratory confirmed varicella patient under 15 years of age diagnosed at 14 designated pediatric clinics between September 2015 and September 2016. Controls were selected from patients who visited the same practice for different reasons as the varicella case within 2 weeks. Swab samples were collected from varicella suspected patients and molecular diagnostic assays were used to confirm varicella cases. Matched odds ratio were used to calculate vaccine effectiveness (VE).ResultsVaricella zoster virus DNA was detected in 183 (81.3%) of 225 suspected cases. One sample was excluded because it was positive for the Oka vaccine strain (182/225, 80.9%). Three hundred twenty-three control subjects were enrolled. The effectiveness of 1 dose of the Oka/Biken vaccine compared with no vaccine was 76.7% (95% confidence interval [CI]: 58.6–86.9%; P < 0.001). The effectiveness of 2 doses of the Oka/Biken vaccine was 94.2% (95% CI: 85.7–97.6%; P < 0.001). After adjusting for potential confounding effects, the adjusted VE of 1 and 2 doses of varicella vaccine were 76.9% (95% CI: 58.1–87.3%; P < 0.001) and 94.7% (95% CI: 86.0–98.0%; P < 0.001), respectively.ConclusionsVE of one dose of Oka/Biken varicella vaccine was insufficient to control varicella. Therefore, two doses of Oka/Biken varicella vaccine is significant for controlling varicella in Japan.     

Meningococcal C conjugate age-dependant long-term loss of effectiveness

IntroductionAlthough different epidemiological studies have assessed meningococcal C conjugate vaccine effectiveness within 1 and >1 year since vaccination, none of them evaluated long-term effectiveness. In order to assess if epidemiological data correlates with the findings described in seroprevalence studies we evaluated long-term vaccine effectiveness over time, up to 10 years since vaccination.MethodsCases targeted by vaccination programs and notified to the Spanish Surveillance System between 2001 and 2013 were included in the study. Vaccine effectiveness was estimated using the screening method. Relationship between vaccine effectiveness and time since vaccination was explored using point estimates, simple logistic regression or restricted cubic splines logistic regression model for all and for those vaccinated at <1, 1–11 and at 12–19 years of age.ResultsFrom 345 confirmed cases reported in the period and targeted by vaccination programs, 125 (36.23%) were vaccine failures. Proportion of vaccine failures decreased with age of vaccination: 63.97% at <1 year; 36.84% at 1–11 years; and 3.88% at 12–19 years. Using the best model for each group, vaccine effectiveness decreased from 99.12% to 90.85% (%change = −8.3%) for all; from 99.04% to 48.60% (%change = −50.9%) for those vaccinated at <1 years and from 99.45% to 90.18% (%change = −9.3%) for those vaccinated at 1–11 years after 10 years since vaccination. For those vaccinated at 12–19 years no changes were observed in vaccine effectiveness after 10 years (p = 0.968).ConclusionsAfter 10 years, vaccine effectiveness decreased by 50% in those vaccinated at <1 year, while those vaccinated with one dose at 12–19 years showed no changes. Vaccine failures occurred early after vaccination and more frequently in those vaccinated at younger ages. Vaccination at ≥12 years seems to be related to a low number of vaccine failures and a higher and endurable protection over time.     

Effectiveness of different vaccine schedules for heptavalent and 13-valent conjugate vaccines against pneumococcal disease in the Community of Madrid

IntroductionThe heptavalent pneumococcal conjugate vaccine (PCV-7) was added to the childhood routine vaccination program in the Community of Madrid in November of 2006 with 3 + 1 recommended doses and a catch-up for those under 2 years old. In June 2010, PCV-7 was replaced by 13-valent vaccine (PCV-13) with 2 + 1 recommended doses. In July of 2012, the PCV-13 was removed from the funded program and reintroduced again (2 + 1 recommended doses) in December 2014. In between, children were vaccinated privately with 3 + 1 recommended doses of PCV-13. The aim of this study was to evaluate the effectiveness of each vaccination schedule used in the Community of Madrid.MethodsWe included all cases of invasive pneumococcal disease (IPD) reported between 2007 and 2015 to the Notifiable Diseases Surveillance System. Vaccination information was obtained from the Immunization Registry. Vaccine effectiveness (VE) was estimated using the indirect cohort design for cases with serotype information.ResultsA total 779 cases were included in the study. Among them 47.6% of the cases were primo-vaccinated with booster, 20% primo-vaccinated, 15.9% incompletely primo-vaccinated and 16.5% not vaccinated. The VE for ≥1 doses of any PCV was 82% (CI 95%: 67.8–89.9%): 91.9% (CI 95%: 76.5–97.2%) for PCV-7 and 77.2% (48.6–89.9%) for PCV-13. VE in those receiving the full 2 + 1 or 3 + 1 schedules was 100% for both vaccines.ConclusionsA high number of vaccine failures were reported in children before they had the opportunity to receive the booster dose, especially due to PCV-13-non-PCV-7 serotypes. VE was higher for PCV-7 compared to PCV-13, except for those that received the complete schedule with booster that achieved 100% of VE, which shows the relevance of the vaccines and complying with all doses scheduled.