Influenza and Tetanus, Diphtheria, and Acellular Pertussis Vaccination During Pregnancy, Pregnancy Risk Assessment Monitoring System, 2019

Background Influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines is recommended for pregnant women to protect themselves and their infants from adverse health outcomes. Objectives To estimate the prevalence of maternal influenza and Tdap vaccination and determine factors associated with receipt of these vaccines. Methods We analyzed 2019 data from the Pregnancy Risk Assessment Monitoring System, from 43 jurisdictions. We estimated the overall prevalence of women reporting receipt of a healthcare provider offer or recommendation for influenza vaccine (n=44,528), and influenza vaccine during the 12 months before delivery (n=44,213). We also estimated Tdap vaccine receipt during pregnancy from the 21 jurisdictions (n=22,972). Maternal influenza and Tdap vaccination were examined by selected maternal characteristics and by jurisdiction. Results Overall, 86.4% of women reported being offered or recommended an influenza vaccination, and 60.8% of women reported receiving an influenza vaccination in the 12 months prior to their delivery, ranging from 36.0% in Puerto Rico to 82.1% in Rhode Island. Tdap receipt during pregnancy was 73.7%, ranging from 52.2% in Mississippi to 85.1% in Vermont. Prevalence of influenza vaccination was lower among women aged 18–24 years (52.2%), who are non-Hispanic black (44.5%), with a high school diploma or less education (51.3%), with no prenatal insurance (43.2%), having no (42.0%) prenatal care, with ≥3 previous live births (49.3%) and not offered or recommended the influenza vaccine by a healthcare provider (20.0%). Tdap vaccination also varied by all characteristics examined and was lower among similar groups of women observed to have lower influenza vaccination uptake. Conclusion In 2019, influenza and Tdap vaccination were suboptimal among women with a recent live birth. It is important that U.S. jurisdictions provide equitable access to these vaccines during pregnancy. These results may also inform efforts for vaccination for other infectious diseases among pregnant women.

An evaluation of strategies to achieve greater than 90% coverage of maternal influenza and pertussis vaccines including an economic evaluation

Background Maternal immunisation is an essential public health intervention aimed at improving the health outcomes for pregnant women and providing protection to the newborn. Despite international recommendations, safety and efficacy data for the intervention, and often a fully funded program, uptake of vaccines in pregnancy remain suboptimal. One possible explanation for this includes limited access to vaccination services at the point of antenatal care. The aim of this study is to evaluate the change in vaccine coverage among pregnant women following implementation of a modified model of delivery aimed at improving access at the point of antenatal care, including an economic evaluation. Methods This prospective multi-centre study, using action research design, across six maternity services in Victoria, Australia, evaluated the implementation of a co-designed vaccine delivery model (either a pharmacy led model, midwife led model or primary care led model) supported by provider education. The main outcome measure was influenza and pertussis vaccine uptake during pregnancy and the incremental cost of the new model (compared to existing models) and the cost-effectiveness of the new model at each participating health service. Results Influenza vaccine coverage in 2019 increased between 50 and 196% from baseline. All services reduced their average cost per immunisation under the new platforms due to efficiencies achieved in the delivery of maternal immunisations. This cost saving ranged from $9 to $71. Conclusion Our study demonstrated that there is no ‘one size fits all’ model of vaccine delivery. Future successful strategies to improve maternal vaccine coverage at other maternity services should be site specific, multifaceted, targeted at the existing barriers to maternal vaccine uptake, and heavily involve local stakeholders in the design and implementation of these strategies. The cost-effectiveness analysis indicates that an increase in maternal influenza immunisation uptake can be achieved at a relatively modest cost through amendment of maternal immunisation platforms.

Offspring born to influenza A virus infected pregnant mice have increased susceptibility to viral and bacterial infections in early life

Influenza during pregnancy can affect the health of offspring in later life, among which neurocognitive disorders are among the best described. Here, we investigate whether maternal influenza infection has adverse effects on immune responses in offspring. We establish a two-hit mouse model to study the effect of maternal influenza A virus infection (first hit) on vulnerability of offspring to heterologous infections (second hit) in later life. Offspring born to influenza A virus infected mothers are stunted in growth and more vulnerable to heterologous infections (influenza B virus and MRSA) than those born to PBS- or poly(I:C)-treated mothers. Enhanced vulnerability to infection in neonates is associated with reduced haematopoetic development and immune responses. In particular, alveolar macrophages of offspring exposed to maternal influenza have reduced capacity to clear second hit pathogens. This impaired pathogen clearance is partially reversed by adoptive transfer of alveolar macrophages from healthy offspring born to uninfected dams. These findings suggest that maternal influenza infection may impair immune ontogeny and increase susceptibility to early life infections of offspring.

Influenza vaccination during pregnancy and influencing factors in Korea: A multicenter questionnaire study of pregnant women and obstetrics and gynecology doctors

Background Although the World Health Organization and health authorities in most countries recommend that pregnant women receive inactivated influenza virus vaccines, coverage remains low. This study aimed to investigate (1) the proportion of pregnant women who received an influenza vaccination and influencing factors and (2) the proportion of obstetrics and gynecology (OBGYN) doctors who routinely recommend influenza vaccination to pregnant women and influencing factors. Methods Two separate, anonymized questionnaires were developed for physicians and pregnant and postpartum women and were distributed to multicenters and clinics in South Korea. The proportions of women who received influenza vaccination during pregnancy and OBGYN doctors who routinely recommend the influenza vaccine to pregnant women were analyzed. Independent influencing factors for both maternal influenza vaccination and OBGYN doctors’ routine recommendations to pregnant women were analyzed using log-binomial regression analysis. Results The proportion of self-reported influenza vaccination during pregnancy among 522 women was 63.2%. Pregnancy-related independent factors influencing maternal influenza vaccination were “(ever) received information about influenza vaccination during pregnancy” (OR 8.9, 95% CI 4.17–19.01), “received vaccine information about from OBGYN doctors” (OR 11.44, 95% CI 5.46–24.00), “information obtained from other sources” (OR 4.38, 95% CI 2.01–9.55), and “second/third trimester” (OR 2.41, 95% CI 1.21–4.82).. Among 372 OBGYN doctors, 76.9% routinely recommended vaccination for pregnant women. Independent factors effecting routine recommendation were “working at a private clinic or hospital” (OR 5.33, 95% CI 2.44–11.65), “awareness of KCDC guidelines” (OR 3.11, 95% CI 1.11–8.73), and “awareness of the 2019 national free influenza vaccination program for pregnant women” (OR 4.88, 95% CI 2.34–10.17). OBGYN doctors most commonly chose ‘guidelines proposed by the government or public health (108, 46%) and academic committees (59, 25%), as a factor which expect to affect the future recommendation Conclusion This study showed that providing information about maternal influenza vaccination, especially by OBGYN doctors, is crucial for increasing vaccination coverage in pregnant women. Closer cooperation between the government and OBGYN academic societies to educate OBGYN doctors might enhance routine recommendations.

Childhood seizures after prenatal exposure to maternal influenza infection: a population-based cohort study from Norway, Australia and Canada

ObjectiveTo assess whether clinical and/or laboratory-confirmed diagnosis of maternal influenza during pregnancy increases the risk of seizures in early childhood.DesignAnalysis of prospectively collected registry data for children born between 2009 and 2013 in three high-income countries. We used Cox regression to estimate country-level adjusted HRs (aHRs); fixed-effects meta-analyses were used to pool adjusted estimates.SettingPopulation-based.Participants1 360 629 children born between 1 January 2009 and 31 December 2013 in Norway, Australia (New South Wales) and Canada (Ontario).ExposureClinical and/or laboratory-confirmed diagnosis of maternal influenza infection during pregnancy.Main outcome measuresWe extracted data on recorded seizure diagnosis in secondary/specialist healthcare between birth and up to 7 years of age; additional analyses were performed for the specific seizure outcomes ‘epilepsy’ and ‘febrile seizures’.ResultsAmong 1 360 629 children in the study population, 14 280 (1.0%) were exposed to maternal influenza in utero. Exposed children were at increased risk of seizures (aHR 1.17, 95% CI 1.07 to 1.28), and also febrile seizures (aHR 1.20, 95% CI 1.07 to 1.34). There was no strong evidence of an increased risk of epilepsy (aHR 1.07, 95% CI 0.81 to 1.41). Risk estimates for seizures were higher after influenza infection during the second and third trimester than for first trimester.ConclusionsIn this large international study, prenatal exposure to influenza infection was associated with increased risk of childhood seizures.