Understanding the impact of adult pertussis and current approaches to vaccination: A narrative review and expert panel recommendations.

Pertussis has several notable consequences, causing economic burden, increased strain on healthcare facilities, and reductions in quality of life. Recent years have seen a trend toward an increase in pertussis cases affecting older children and adults. To boost immunity, and protect vulnerable populations, an enduring approach to vaccination has been proposed, but gaps remain in the evidence surrounding adult vaccination that are needed to inform such a policy. Gaps include: the true incidence of pertussis and its complications in adults; regional variations in disease recognition and reporting; and incidence of severe disease, hospitalizations, and deaths in older adults. Better data on the efficacy/effectiveness of pertussis vaccination in adults, duration of protection, and factors leading to poor vaccine uptake are needed. Addressing the critical evidence gaps will help highlight important areas of unmet need and justify the importance of adult pertussis vaccination to healthcare professionals, policymakers, and payers.

Surveillance for adverse events following immunization with DTaP-containing combination vaccines in Linping, China, 2019-2022.

Background: The DTaP-Hib and DTaP-IPV/Hib combination vaccine can be used as a substitute for the diphtheria, tetanus, and acellular pertussis combined vaccine (DTaP). We aimed to evaluate the safety of multi-component vaccines containing DTaP by analyzing the reporting rates and characteristics of adverse events following immunization (AEFIs) in Linping District during the years 2019 to 2022. Methods: We obtained data of AEFI and vaccination from the National AEFI Surveillance System of China and Zhejiang Municipal Immunization Information Management System, respectively, during 2019-2022 for a descriptive, epidemiological analysis. Results: The total number of AEFI reported following vaccinations with DTaP-containing combination vaccines was 802 in Linping District from 2019 to 2022. The overall reporting rates of AEFIs following DTaP, DTaP-Hib, and DTaP-IPV/Hib vaccinations were 445.72 (537 cases), 536.29 (45 cases), and 306.13 (220 cases) per 100,000 doses in Linping District from 2019 to 2022, respectively. Only one case of a serious AEFI following DTaP vaccination, with a reporting rate of 0.83 per 100,000 doses. The composition ratio of vaccine product-related reactions for DTaP, DTaP-Hib, and DTaP-IPV/Hib were 99.81, 97.78, and 100.00%, respectively. The composition ratio of coincidental events for DTaP and DTaP-Hib were 0.19 and 2.22%, respectively. The reporting rates of total AEFIs for DTaP-IPV/Hib were lower than for DTaP. The reporting rate of local induration for DTaP-Hib was lower than for DTaP, and the reporting rates of local redness & swelling and local induration for DTaP-IPV/Hib were both lower than for DTaP. DTaP-IPV/Hib had a higher proportion of AEFIs in first quarter compared to DTaP. The reporting rate after the second dose of DTaP-Hib was higher than that of DTaP, and the reporting rates of AEFIs after the first dose and third dose of DTaP-IPV/Hib were lower than DTaP. Conclusion: The reported AEFIs to multi-component vaccines containing DTaP components during 2019-2022 in Linping District were mainly mild vaccine reactions. DTaP-containing combination vaccines demonstrated a good safety profile.

Immunogenicity at delivery after Tdap vaccination in successive pregnancies.

Background: Tetanus, diphtheria, acellular pertussis (Tdap) vaccination is recommended to be administered in every pregnancy. Although the safety of this strategy has been confirmed, the immunogenicity of Tdap vaccination in two successive pregnancies has not yet been described. This study investigated Tdap-specific immunity levels and transplacental transfer in two successive pregnancies after repeated Tdap-vaccination. Methods: Women enrolled in prior studies on Tdap vaccination during pregnancy were invited to participate in a follow-up study if they became pregnant again. Women who received a Tdap vaccine in both pregnancies were considered for this analysis. Tdap-specific total IgG and IgG subclasses were measured with a multiplex immunoassay. Results: In total, 27 participants with a mean interval between deliveries of 2.4 years were included in the analysis. In maternal serum, Tdap-specific total IgG levels were comparable at both deliveries whereas in cord serum, all Tdap-specific total IgG antibody levels were reduced at the second compared to the first delivery. This was largely reflected in the IgG1 levels in maternal and cord serum. Transplacental transfer ratios of total IgG and IgG1 were also mostly reduced in the second compared to the first pregnancy. Conclusion: This study reports for the first time Tdap-specific total IgG and IgG subclass levels and transfer ratios after repeated Tdap vaccination in successive pregnancies. We found reduced transfer of most Tdap-specific IgG and IgG1 antibodies in the successive pregnancy. As pertussis-specific antibodies wane quickly, Tdap vaccination in each pregnancy remains beneficial. However, more research is needed to understand the impact of closely spaced booster doses during pregnancy on early infant protection against pertussis.

Vaccination during pregnancy and modulation of IgG response to pertussis vaccines in infants: The impact of different vaccine formulations.

The IgG response following infant diphtheria-tetanus-acellular pertussis (DTaP) immunization is influenced by the formulation of the infant and/or the adult vaccine (Tdap) given during pregnancy. DTaP vaccines containing either 3 (DTaP3) or 5 (DTaP5) pertussis antigens are commonly used. By conducting a secondary analysis of a large randomized controlled trial, we compared IgG levels against pertussis vaccine antigens in children of Td- and Tdap5-vaccinated mothers, after stratifying by infant vaccine formulation. After immunization with a primary series of DTaP5, but not DTaP3, IgG GMCs against pertussis antigens were significantly lower in infants of Tdap-immunized mothers compared with infants of Td-vaccinated mothers (pertussis toxin: GMC = 52.3[Tdap5] vs 83.5[Td], p < 0.001). Before and after the DTaP booster dose, IgG GMCs were similar in infants of Tdap- and Td-immunized mothers specifically when infants received the DTaP3 vaccine. The combination of the TdaP5 vaccine for mothers and the DTaP3 vaccine for children could attenuate Tdap-associated immunomodulation.

Quantitative analysis of pertussis, tetanus, and diphtheria antibodies in sera and breast milk from Tdap vaccinated women using a qualified multiplex assay.

Pertussis (whooping cough) is a reemergent, highly contagious respiratory infection of public health concern. Infants prior to initiation of their primary vaccination series are the most vulnerable to severe infection, and even death. Vaccination during pregnancy is an efficacious means of reducing infection in infants. This approach relies on boosting maternal immunity and passive transfer of antibodies to the infant via placenta and breast milk. Similarly, maternal vaccination post-partum can enhance maternal-infant immunity. To support the analysis of pertussis immunity in the context of maternal-infant immunization, we developed a high throughput multiplex assay for simultaneous quantification of serum IgG antibodies against pertussis vaccine antigens: pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae (FIM2/3), and against tetanus (TT) and diphtheria toxoids (DT), using the Meso Scale Discovery (MSD) platform. The assay was qualified, and specificity, sensitivity, accuracy, precision, linearity, and robustness were demonstrated. The assay was subsequently adapted for quantification of IgG and IgA in breast milk. Applied to a serological survey of pregnant women living in the United States and sub-Saharan Africa, this method revealed differences in magnitude and breadth of antibody profile, consistent with history of vaccination. A longitudinal analysis of Tdap responses in women vaccinated post-partum demonstrated a rapid increase in serum IgG that remained elevated for up to 24 months. Likewise, high levels of vaccine-specific IgA and IgG antibodies were present in breast milk, although they exhibited faster decay. This multiplex MSD assay is a reliable and practical tool for quantification of pertussis, tetanus, and diphtheria antibodies in serum and breast milk in serosurveys or vaccine studies. IMPORTANCE: Pertussis (whooping cough) has reemerged in recent years. Vaccination during pregnancy is an effective approach to prevent illness during the first months of life. We developed a multiplex assay for quantification of pertussis, tetanus, and diphtheria serum antibodies using the Meso Scale Discovery (MSD) platform; the method was qualified, and specificity, precision, accuracy, linearity, and limits of quantification were defined. It was also adapted for quantification of antibodies in breast milk. We successfully determined serostatus in women from different regions and with different vaccination histories, as well as responses to Tdap in blood and breast milk post-partum. This is the first description of a multiplex assay for the quantification of pertussis, tetanus, and diphtheria antibodies in breast milk.

Antiviral responses induced by Tdap-IPV vaccination are associated with persistent humoral immunity to Bordetella pertussis.

Many countries continue to experience pertussis epidemics despite widespread vaccination. Waning protection after booster vaccination has highlighted the need for a better understanding of the immunological factors that promote durable protection. Here we apply systems vaccinology to investigate antibody responses in adolescents in the Netherlands (N = 14; NL) and the United Kingdom (N = 12; UK) receiving a tetanus-diphtheria-acellular pertussis-inactivated poliovirus (Tdap-IPV) vaccine. We report that early antiviral and interferon gene expression signatures in blood correlate to persistence of pertussis-specific antibody responses. Single-cell analyses of the innate response identified monocytes and myeloid dendritic cells (MoDC) as principal responders that upregulate antiviral gene expression and type-I interferon cytokine production. With public data, we show that Tdap vaccination stimulates significantly lower antiviral/type-I interferon responses than Tdap-IPV, suggesting that IPV may promote antiviral gene expression. Subsequent in vitro stimulation experiments demonstrate TLR-dependent, IPV-specific activation of the pro-inflammatory p38 MAP kinase pathway in MoDCs. Together, our data provide insights into the molecular host response to pertussis booster vaccination and demonstrate that IPV enhances innate immune activity associated with persistent, pertussis-specific antibody responses.

Attitudes and behaviors of maternal Tdap vaccination in Panama, Peru, and Colombia: An international cross-sectional study.

INTRODUCTION: Despite a recommendation by PAHO for Tdap vaccination in pregnant women since 2019, uptake remains suboptimal across Latin America. This study evaluated the knowledge and attitudes of women towards maternal Tdap vaccination in Colombia, Peru, and Panama to identify the critical behavioral and social drivers of Tdap vaccine uptake during pregnancy. METHODS: A cross-sectional online survey was undertaken between December 8, 2022, and January 11, 2023, targeting women in Colombia, Peru, or Panama with a child 12 months or under. We collected data on respondents' demographics, social and behavioral determinants of vaccine acceptance, determinants of vaccine uptake (using the validated 5As taxonomy), and previous vaccination experience. RESULTS: In the 938 respondents who completed the survey (Panama, n = 325; Peru, n = 305; Colombia, n = 308), 73-80 % had received the influenza vaccine, whereas only 30-39 % had received a Tdap vaccine. Significant correlates of Tdap vaccine uptake common to all three countries included a health professional recommendation, knowledge of the vaccine and location of vaccination, perceived vulnerability to pertussis infection, perceived importance of immunization, and receipt of a reminder. In specific countries, nonvaccinated women were more likely to cite issues with ease of access (Panama, Colombia), affordability (opportunity costs; Peru, Colombia), and understanding the rationale for vaccination in pregnancy (Panama, Colombia). CONCLUSION: To increase maternal Tdap vaccine uptake, health professionals should be encouraged to recommend vaccination consistently, and pregnant women should receive reminders explaining why and where to be vaccinated.

Cost-effectiveness analysis of pertussis booster vaccination for adolescents in Japan.

INTRODUCTION: In Japan, the introduction of a fifth diphtheria-tetanus-acellular pertussis (DTaP) vaccination has been considered, and adolescents aged 11-12 years old who are currently receiving the diphtheria-tetanus (DT) vaccine are one candidate group. We analyze the cost-effectiveness of replacing the DT vaccine with the DTaP vaccine for 11-year-old adolescents and investigate the indirect effect of vaccinated adolescents on unvaccinated infant siblings. We undertake two analyses using high- and low-morbidity pertussis cases, and based on the results, present suggestions for pertussis prevention in the post-COVID-19 pandemic era. METHOD: We used the number of pertussis cases in 2019 as the high-morbidity case and the average number of cases in 2020-2021 as the low-morbidity case, and evaluated the incremental cost-effectiveness ratio (ICER) of the DTaP strategy to the DT strategy based on quality-adjusted life years (QALYs). The economic model contained adolescent and infant sub-models. The indirect effect for infants was considered as the probability of unvaccinated infants avoiding pertussis infection from their vaccinated siblings. RESULTS: The ICER from the payers' perspective was Japanese yen (JPY) 4,254,515 per QALY gained in the high-morbidity case and JPY 62,546,776 per QALY gained in the low-morbidity case. The sensitivity analysis showed that the utility of pertussis had the greatest impact on the ICER, with a 60.58% and 0% probability that the ICER was less than JPY 5 million per QALY gained in the high-morbidity case and low-morbidity case, respectively. CONCLUSION: The cost-effectiveness of replacing the DT vaccine with the DTaP vaccine is affected by the level of pertussis morbidity, with the ICER becoming more favorable in the high-morbidity case. The indirect effect has little impact on the ICER. Thus, policy-makers should continue to monitor the pertussis epidemic in the post-COVID-19 era, and determine the need to introduce a booster based on perceived trends.

Co-administration of the adjuvanted recombinant zoster vaccine with other adult vaccines: An overview.

BACKGROUND: The adjuvanted recombinant zoster vaccine (RZV; Shingrix®, GSK) is a subunit vaccine that has been approved for the prevention of herpes zoster in adults. Co-administration of two vaccines in a single visit is a strategy to improve overall vaccine coverage. OBJECTIVES: This review aims to consolidate available clinical data on RZV co-administration, providing an overview of safety, reactogenicity and immunogenicity. METHODS: RZV co-administration data were obtained from five randomised, open-label, phase III clinical trials with similar study designs. The co-administered vaccines included: quadrivalent seasonal inactivated influenza vaccine (IIV4; NCT01954251), 23-valent pneumococcal polysaccharide vaccine (PPSV23; NCT02045836), reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine (Tdap; NCT02052596), 13-valent pneumococcal conjugate vaccine (PCV13; NCT03439657) and COVID-19 mRNA-1273 booster (NCT05047770). Eligible participants were healthy adults aged ≥50 years. RESULTS: A total of 3,974 participants were vaccinated (co-administration: 1,973; sequential: 2,001) across the five trials. Vaccine response rates to RZV were similar for co-administration (range: 95.8-99.1 %) and sequential groups (range: 95.1-99.1 %). Immune responses to RZV and the other vaccines (with the exception of pertactin) were non-inferior when the vaccines were co-administered compared with sequentially administered. Overall incidences of solicited local and general adverse events (AEs), unsolicited AEs, serious AEs or potential immune-mediated diseases were similar after co-administration or sequential administration. Myalgia was the most common solicited systemic AE (co-administration: 38-64 %; sequential: 30-59 %). Shivering and fever were more common after co-administration (16 % and 21 %, respectively) than after sequential administration (both 7 %) of RZV and PPSV23. CONCLUSIONS: Co-administration of RZV with routine vaccines does not significantly alter the reactogenicity, immunogenicity or safety of RZV or the co-administered vaccine. Healthcare practitioners should consider routine co-administration of RZV with other adult vaccines to improve vaccination coverage.

Antenatal tetanus, diphtheria, and acellular pertussis (Tdap) immunization and risk of serogroup 19 IPD in children: An indirect cohort study.

The tetanus-diphtheria-acellular pertussis (Tdap) vaccine has been indicated for pregnant women in Quebec, Canada since 2018. Recent literature suggests maternal Tdap interferes with the pneumococcal vaccine response in children exposed in utero because of maternally transferred anti-diphtheria antibodies, a phenomenon known as blunting. Using an indirect cohort study, we investigated whether maternal Tdap vaccination could alter the protection of PCV vaccines against serotype 19A/F IPD (conjugated to diphtheria toxoid in PCV10). Thirty-seven immunized IPD cases (serotype 19A/F) and 90 immunized IPD controls (non-vaccine serotypes) were analyzed using multivariate logistic regression. Our analyses did not identify antenatal Tdap exposure as a risk factor for IPD in vaccinated children, with and odds ratio close to the null (odds ratio = 0.82, 95%CI = 0.32-2.07). As this study is the first to assess the impact of maternal immunization on pneumococcal disease risk, future investigations involving a larger number of cases should be conducted to confirm or infirm our findings.

BECC438b TLR4 agonist supports unique immune response profiles from nasal and muscular DTaP pertussis vaccines in murine challenge models.

The protection afforded by acellular pertussis vaccines wanes over time, and there is a need to develop improved vaccine formulations. Options to improve the vaccines involve the utilization of different adjuvants and administration via different routes. While intramuscular (IM) vaccination provides a robust systemic immune response, intranasal (IN) vaccination theoretically induces a localized immune response within the nasal cavity. In the case of a Bordetella pertussis infection, IN vaccination results in an immune response that is similar to natural infection, which provides the longest duration of protection. Current acellular formulations utilize an alum adjuvant, and antibody levels wane over time. To overcome the current limitations with the acellular vaccine, we incorporated a novel TLR4 agonist, BECC438b, into both IM and IN acellular formulations to determine its ability to protect against infection in a murine airway challenge model. Following immunization and challenge, we observed that DTaP + BECC438b reduced bacterial burden within the lung and trachea for both administration routes when compared with mock-vaccinated and challenged (MVC) mice. Interestingly, IN administration of DTaP + BECC438b induced a Th1-polarized immune response, while IM vaccination polarized toward a Th2 immune response. RNA sequencing analysis of the lung demonstrated that DTaP + BECC438b activates biological pathways similar to natural infection. Additionally, IN administration of DTaP + BECC438b activated the expression of genes involved in a multitude of pathways associated with the immune system. Overall, these data suggest that BECC438b adjuvant and the IN vaccination route can impact efficacy and responses of pertussis vaccines in pre-clinical mouse models.

Influenza and Tetanus, Diphtheria, and Acellular Pertussis Vaccination Coverage During Pregnancy: Pregnancy Risk Assessment Monitoring System, 2020.

OBJECTIVES: Estimates of vaccination coverage during pregnancy and identification of disparities in vaccination coverage can inform vaccination campaigns and programs. We reported the prevalence of being offered or told to get the influenza vaccine by a health care provider (hereinafter, provider); influenza vaccination coverage during the 12 months before delivery; and tetanus, diphtheria, and acellular pertussis (Tdap) vaccination coverage during pregnancy among women with a recent live birth in the United States. METHODS: We analyzed 2020 data from the Pregnancy Risk Assessment Monitoring System from 42 US jurisdictions (n = 41 673). We estimated the overall prevalence of being offered or told to get the influenza vaccine by a provider and influenza vaccination coverage during the 12 months before delivery. We estimated Tdap vaccination coverage during pregnancy from 21 jurisdictions with available data (n = 22 020) by jurisdiction and select characteristics. RESULTS: In 2020, 84.9% of women reported being offered or told to get the influenza vaccine, and 60.9% received it, ranging from 35.0% in Puerto Rico to 79.7% in Massachusetts. Influenza vaccination coverage was lower among women who were not offered or told to get the influenza vaccine (21.4%) than among women who were offered or told to get the vaccine (68.1%). Overall, 72.7% of women received the Tdap vaccine, ranging from 52.8% in Mississippi to 86.7% in New Hampshire. Influenza and Tdap vaccination coverage varied by all characteristics examined. CONCLUSIONS: These results can inform vaccination programs and strategies to address disparities in vaccination coverage during pregnancy and may inform vaccination efforts for other infectious diseases among pregnant women.

Vaccine Immunity in Children After Hematologic Cancer Treatment: A Retrospective Single-center Study.

BACKGROUND: Children lose their vaccine-induced protection and are particularly vulnerable to vaccine-preventable diseases after chemotherapy. However, revaccination guidelines are heterogeneous, and there is often a lack of revaccination post-treatment. AIMS: We conducted a retrospective study of children with hematologic cancer to evaluate vaccine immunity before and after the end of treatment and to determine whether the current institutional revaccination program based on vaccine serology results was followed and effective. MATERIALS AND METHODS: Data of all children treated by chemotherapy between April 2015 and July 2021 were extracted from hospital medical records for analysis. Serum antibody levels and time of vaccination were evaluated for diphtheria, tetanus, Streptococcus pneumoniae , Haemophilus influenzae type b (Hib), measles, varicella, and hepatitis B. RESULTS: We included 31 patients (median age, 9 years). At cancer diagnosis, 90% of children were protected against tetanus, diphtheria, and measles; 65% to 67% were protected against pneumococcus and varicella; and 25% against hepatitis B. At the end of chemotherapy, 67% to 71% of patients were protected against tetanus, varicella, and measles; 40% remained protected against hepatitis B; and 27% to 33% against pneumococcus and diphtheria. Patients were revaccinated at various times after the end of treatment but not systematically. During the first-year post-treatment, 20% to 25% of children remained unprotected against pneumococcus, measles, and hepatitis B, one third against diphtheria, but all were protected against tetanus and varicella. CONCLUSIONS: An effective individualized vaccination program post-cancer based on serology results should be accompanied by an appropriate serology tracking method and follow-up to assess if booster doses are necessary. Our study supports vaccinating all children with a dose of the 13-valent pneumococcal conjugate at cancer diagnosis and at 3 months post-treatment with the combined diphtheria-tetanus-acellular pertussis/poliomyelitis vaccine/hepatitis B virus plus or minus Hib and 13-valent pneumococcal conjugate and meningococcal vaccine, including measles/mumps/rubella-varicella zoster virus vaccine if good immune reconstitution is present.

Effective and safe transfer of maternal antibodies persisting two months postpartum following maternal immunization with different doses of recombinant pertussis-containing vaccines.

INTRODUCTION: Recombinant acellular pertussis (ap) vaccines containing genetically inactivated pertussis toxin (PTgen) and filamentous hemagglutinin (FHA) with or without tetanus (TT) and diphtheria (DT) vaccines (Td) were found safe and immunogenic in non-pregnant and pregnant women. We report here maternal antibody transfer and safety data in mothers and neonates. METHODS: This is the follow up of a phase 2 trial in 2019 among 400 pregnant women who randomly received one dose of recombinant pertussis-only vaccine containing 1 µg PTgen and 1 µg FHA (ap1gen), or Td combined with ap1gen (Tdap1gen), or with 2 µg PTgen and 5 µg FHA (Tdap2gen), or with 5 µg PTgen and 5 µg FHA (TdaP5gen, Boostagen®, BioNet, Thailand) or chemically-inactivated acellular pertussis comparator (Tdap8chem, Boostrix™, GSK, Belgium), either in the second or third trimester of gestation. IgG against PT, FHA, TT and DT were assessed by ELISA, PT-neutralizing antibodies (PTNA) by Chinese Hamster Ovary cell assay and safety outcomes at delivery in mothers and at birth. RESULTS: Anti-PT and anti-FHA geometric mean concentration (GMC) ratio between infants at birth and mothers at delivery was above 1 in all groups. PT GMC in infants at birth were ≥30 IU/mL in all groups with the highest titers in infants found in TdaP5gen group at birth (118.8 [95% CI 93.9-150.4]). At 2 months, PT GMC ratio to Tdap8chem (98.75% CI) was significantly higher for TdaP5gen (2.6 [1.7-4.0]) and comparable for other recombinant vaccines. No difference in PTNA titers at birth was observed between all groups nor between time of vaccination. Adverse events were comparable in all vaccine groups. CONCLUSIONS: BioNet licensed (TdaP5gen and Tdap2gen) and candidate vaccines (Tdap1gen and ap1gen) when given to pregnant women in the second or third trimester of gestation are safe and have induced passive pertussis immunity to infants.

A Multivariate Probit Regression of the Uptake of Adolescent Vaccines Among Racial/Ethnic Minority Adolescents Before and During the COVID-19 Pandemic.

PURPOSE: The uptake of adolescent vaccines has improved over the years. However, research of the effects of the COVID-19 pandemic on this uptake among racial/ethnic minority adolescents has been limited. This study was conducted to compare the probability of uptake of the human papillomavirus (HPV); tetanus, diphtheria, and acellular pertussis (Tdap); and quadrivalent meningococcal conjugate (MenACWY) vaccines among racial/ethnic minority adolescents ages 13-17 years in 2019, 2020, and 2021. METHODS: Using a cross-sectional design to examine data from the National Immunization Survey-Teen (2019-2021), multivariate probit regression was used to model variation in uptake of these three adolescent vaccines (n = 38,128). The outcome measures were HPV, Tdap, and MenACWY vaccine uptake. RESULTS: The probability of uptake of HPV vaccine was higher in 2020 (Coef = 0.09 [95% confidence interval (CI), 0.03-0.16]) and 2021 (Coef = 0.07 [95% CI, 0.00-0.15]) than in 2019. The probability of uptake of MenACWY vaccine was higher in 2020 (Coef = 0.08 [95% CI, 0.02-0.15]) than in 2019. The probability of uptake of recommended vaccines varied among racial/ethnic minorities with non-Hispanic Black adolescents exhibiting higher probability of uptake of HPV vaccine (Coef = 0.10 [95% CI, 0.01-0.19]) than Tdap vaccine. U.S. Census region and insurance status were associated with the uptake of all recommended vaccines. DISCUSSION: Progress in the uptake of these recommended vaccines may not have been interrupted by the COVID-19 pandemic. Also, disparities in uptake of the recommended vaccines still exist despite increased uptake during the pandemic. Future research should examine the disparities as well as examine regional differences in the uptake of these three adolescent vaccines.

Achieving Equity in Childhood Vaccination: A Mixed-Methods Study of Immunization Programs, Policies, and Coverage in 3 US States.

OBJECTIVE: In this study, we sought to understand patterns of childhood vaccinations in the United States across socioeconomic and racial/ethnic groups over a 12-year period to identify interventions that improve immunization equity and inform public health practice. DESIGN: We conducted an explanatory, sequential, mixed-methods study. US state- and county-level immunization data were analyzed to understand trends in immunization coverage among racial/ethnic groups. Qualitative interviews with public health and community leaders were used to explain trends, gain insight into routine childhood immunization interventions, and understand local contexts and data limitations. PARTICIPANTS AND SETTING: Secondary data were used from the National Immunization Survey-Child (NIS) public use data sets (2007 and 2019). Eligible participants for qualitative interviews were routine childhood immunization stakeholders from selected counties in North Carolina, Washington, and Arizona. MAIN OUTCOME MEASURE: Our integrated findings report trends and probability of children aged 19 months to 3 years being fully vaccinated (measles-mumps-rubella [MMR], diphtheria and tetanus toxoids and acellular pertussis [DTaP], hepatitis B [Hep B]), interventions, and recommendations to improve routine childhood immunization coverage and equity. RESULTS: Vaccination coverage remained high and relatively stable between 2007 and 2019; however, there were differences across racial/ethnic groups. Public health leaders identified key interventions that effectively improved vaccine equity and coverage, including data quality improvement, tailored interventions for specific populations, multisector partnerships, addressing common barriers, and data limitations. Participants also identified the critical role of state policies, public health funding, and community vaccine norms. CONCLUSIONS: Variability persists in vaccination coverage and equity across states, race/ethnicity, and socioeconomic status despite decades of interventions. Vaccine stakeholders should use our findings to improve coverage and reduce disparities. Equitable improvements can be realized through policy change, data tracking/infrastructure improvements, and tailored interventions. Furthermore, local partners are critical in improving vaccine coverage and equitable interventions to disrupt disparities that long hold true for vaccine-preventable diseases.

Maternal Tdap and influenza vaccination uptake 2017-2021 in the United States: Implications for maternal RSV vaccine uptake in the future.

BACKGROUND: Assessment of maternal vaccine coverage is important for understanding and quantifying the impact of currently recommended vaccines as well as modeling the potential impact of future vaccines. However, existing data lack detail regarding uptake according to week of gestational age (wGA). Such granularity is valuable for more accurate estimation of vaccine impact. OBJECTIVE: To summarize contemporary maternal Tdap vaccination uptake, overall, yearly, and by wGA, and maternal influenza vaccination uptake, overall, by influenza observation year, immunization month, and delivery month, in the US. METHODS: Female patients 18-49 years of age with a pregnancy resulting in a live born infant (i.e., delivery) between 2017 and 2021 were selected from the Optum electronic health records (EHRs) database. Recently published gestational age algorithms were utilized to estimate wGA. RESULTS: Of 1,021,260 deliveries among 886,660 women between 2017-2021, 55.1% had Tdap vaccination during pregnancy; vaccine coverage varied slightly by year (2017: 56.6%; 2018: 55.2%; 2019: 55.2%; 2020: 54.7%; 2021: 52.1%). Most (64.4%) maternal Tdap vaccinations occurred 27-32 wGA; 79.5% occurred during the entire 10-week recommended vaccination window (27-36 wGA). In the evaluation of influenza vaccination uptake (n=798,113 deliveries; 714,841 women), 33.5% of deliveries had influenza vaccination during influenza observation years 2017-2021, most (73.0%) of which occurred during influenza peak activity months (October-January) with approximately one-quarter (27.0%) of vaccinations having occurred during the off-peak months, mostly in September. CONCLUSIONS: In this large contemporary analysis of EHR data, uptake of Tdap vaccination during pregnancy was consistent with previously published estimates; notably, most vaccination occurred early in the recommended 27-36 wGA window. Maternal influenza vaccination uptake largely correlated with peak influenza activity months and not gestational age. These study findings may have important implications for estimating the potential uptake and impact of future maternal vaccines.

Effect of immunization registry-based provider reminder to initiate HPV vaccination at age 9, Washington state.

Human papillomavirus (HPV) vaccination rates are lower than Tetanus-diphtheria-pertussis (Tdap) and Meningococcal conjugate (MenACWY) rates, although the Advisory Committee on Immunization Practices recommends all three vaccines be given routinely at age 11-12. Evidence is mounting that children who initiate HPV vaccination starting at age 9 are more likely to complete the series on time. Washington state implemented a provider reminder through its immunization information system (WAIIS) in January 2023 to increase HPV vaccine initiation at 9-years-old by updating the forecasted recommended age for HPV from age 11 to 9. The effectiveness of provider reminders when implemented via an immunization information system (IIS) is poorly understood. We evaluated the impact of this forecast update using a seasonally adjusted interrupted time series regression of weekly HPV initiations at 9-years-old before and after implementation. We also examined time series trends of vaccine administration between 2018 and 2023 for HPV initiation at age 9, as well as Tdap, MenACWY and HPV initiation at age 11. The WAIIS forecast update doubled the weekly rate of HPV initiation among 9-year-olds in Washington state, although the weekly count of initiation at 9 remains far lower than initiations at 11. Jurisdictions wanting to increase HPV vaccine initiation at earlier ages should consider updating their forecast algorithm and investing in complementary evidence-based strategies such as provider and parent education, and clinic-based quality improvement efforts. The reach of IIS forecaster updates may be enhanced by working with administrators of electronic medical record systems to ensure parity of provider prompts with IIS.

Australian vaccine preventable disease epidemiological review series: tetanus 2003-2019.

Background We examined trends in tetanus notification, hospitalisation and death data from 2003-2019 to assess the impact of adult tetanus booster recommendations in Australia. Methods Tetanus notifications and deaths from the National Notifiable Diseases Surveillance System; hospitalisations from the Australian Institute of Health and Welfare National Hospital Morbidity Database; and deaths from the Australian Coordinating Registry were analysed by age group, sex, Aboriginal and Torres Strait Islander status and state/territory. Annual rates were calculated using Australian Bureau of Statistics mid-year estimated resident populations from 2003-2019 as denominators. To assess the impact of a recommended booster dose of reduced antigen content diphtheria-tetanus-acellular pertussis (dTpa) vaccine for adults aged ≥ 65 years, notification, hospitalisation and death rates of tetanus per 100,000 population were compared pre (2003-2012) and post (2013-2019) the recommendation's introduction. Results There were 63 notifications of tetanus from 2003-2019 with an average annual incidence rate of 0.02/100,000. Similar to previous studies, the burden of tetanus in the Australian population continues to disproportionately affect the elderly, with those aged ≥ 65 years encompassing 63% (40/63) of notifications and 100% (11/11) of the deaths observed in this timeframe. Following the introduction of a recommendation for those aged ≥ 65 years to receive a dTpa booster, average annual notification and hospitalisation rates in those aged ≥ 65 years were significantly lower (notifications: 0.11/100,000 in 2003-2012 and 0.05/100,000 in 2013-2019, p = 0.01; hospitalisations: 0.24/100,000 in 2003-2012 and 0.10/100,000 in 2013-2019, p = 0.01]). The average annual death rate was similar in the two periods (0.002/100,000), although based on small numbers. Conclusions The findings of this analysis suggest a positive impact from the 2013 recommendation. However, the burden is still disproportionately higher in those aged ≥ 65 years and strategies to improve vaccination coverage in older Australians are recommended.

Association between acceptance of routine pregnancy vaccinations and COVID-19 vaccine uptake in pregnant patients.

OBJECTIVE: COVID-19 vaccination is a key approach to reduce morbidity and mortality in pregnant patients and their newborns. Anti-vaccine sentiment has recently increased with unclear impact on pregnant patients. We examined the association between acceptance of tetanus-diphtheria-acellular pertussis (Tdap) and influenza vaccines, considered to be routine pregnancy vaccines, and COVID-19 vaccine acceptance. Secondarily, we identified other predictors of COVID-19 vaccine uptake and described pregnancy outcomes in patients who were and were not vaccinated during pregnancy. METHODS: A retrospective cohort study of all patients who delivered at a single site from December 2020 - March 2022. Demographic, pregnancy, neonatal, and vaccination data were abstracted from the electronic medical record, which imports vaccine history from the California Immunization Registry. The relationship between influenza and Tdap vaccine acceptance, other baseline characteristics, and COVID-19 vaccine uptake was assessed using univariable and multivariable regression analysis. RESULTS: Of the 7857 patients who delivered during the study period, 4410 (56.1%) accepted the COVID-19 vaccine. Of those who received the COVID-19 vaccine, 3363 (97.6%) and 3049 (88.5%) received influenza and Tdap vaccines, respectively. Patients were more likely to receive the COVID-19 vaccine if they had advanced maternal age, obesity, Asian race, and private insurance. After adjustment for baseline differences, COVID vaccine acceptance was associated with receipt of Tdap (aOR 2.10, 95% CI 1.90-2.33) and influenza vaccines (aOR 2.83, 95% CI 2.55-3.14). There were no differences in preterm birth, low birthweight, and NICU admission between patients who received and did not receive the COVID-19 vaccine. CONCLUSION: Patients were more likely to accept COVID-19 vaccination if they received Tdap or influenza vaccinations. Older age, obesity, Asian race, and private insurance were independent predictors of vaccine uptake. Disparities in COVID-19 vaccination uptake bear further exploration to guide efforts in equitable and widespread vaccine distribution.