Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010-11 and 2011-12

Antigen specific vaccine hesitancy in pregnancy

BACKGROUND

Vaccinations in pregnancy are recommended for the potential benefits of preventing severe pertussis disease in newborns and for preventing the impact of influenza on the pregnant woman, her foetus in utero and, the newborn in the first six months of life. Published data in Australia suggested that coverage rates were sub-optimal so the reasons for this were reviewed.

METHODS

A cross-sectional survey of 1014 postnatal women, aged 18 years and older, who had given birth in the previous six months was undertaken on the Gold Coast in Queensland, Australia. Participants completed a brief questionnaire on provided smart tablets at public vaccination clinics or with a researcher by phone or via an on-line link.

RESULTS

Just over 85% of survey respondents received a pertussis booster with many of those not receiving vaccine having had it in a recent pregnancy. Only 36.7% of respondents had an influenza vaccine in pregnancy with key barriers being belief in influenza vaccine, seasonality of parturition and a lack of recommendation from the attending obstetric carers.

DISCUSSION

While maternal pertussis vaccine programs are a success, work needs to be done to improve the public perception of the risk benefit equation surrounding influenza vaccine in general, and particularly its use in pregnancy. Research is required into approaches to altering practitioner attitudes as well as how to alter public perceptions.

Maternal interventions vigilance harmonization in low- and middle-income countries: Stakeholder meeting report; Amsterdam, May 1-2, 2018

Although major reductions in maternal and child mortality were achieved in the Millennium Development Goals era, progress must be accelerated to meet Sustainable Development Goals health targets by 2030. An estimated 2.7 million neonatal deaths and 2.6 million stillbirths still occur annually. Over the past several years there has been renewed global interest in innovative approaches to maternal immunization to potentially decrease mortality and severe morbidity in neonates, and in the pregnant woman and her fetus. Several new vaccines are in clinical development for indications in pregnant women, e.g., vaccines against respiratory syncytial virus, and group B streptococcus. Achieving near-concurrent introduction of new maternal vaccines in high-, middle-, and low-income countries requires that mechanisms are in place for appropriate safety monitoring worldwide.

The Bill & Melinda Gates Foundation convened a global expert meeting in Amsterdam on May 1–2, 2018, to discuss a framework for appropriate pharmacovigilance for vaccines used during pregnancy based on integrated maternal interventions vigilance (MIV) systems and collection of appropriate data to inform timely decision-making by and for pregnant women. Planning for MIV requires a multi-disciplinary, collaborative approach that fully leverages and builds upon existing resources, and builds new capabilities and capacity where needed. Meeting participants identified priority actions including (1) establishing background rates to better evaluate emerging safety signals and vaccine effectiveness, (2) identifying potential sentinel vaccine surveillance sites, (3) developing data sharing capabilities, (4) creating guidance documents and protocols, and (5) the advanced preparation of culturally-appropriate communication plans and risk management plans.

Integrating MIV across the routine obstetric and neonatal health care delivery continuum and all relevant programs and data systems could result in fundamental improvements in maternal, neonatal and child health. Improved pregnancy pharmacovigilance platforms may strengthen other vaccine and drug product safety systems and improve maternal and child research capabilities in LMICs.

Burden, effectiveness and safety of influenza vaccines in elderly, paediatric and pregnant populations

Vaccination is the most practical means available for preventing influenza. Influenza vaccines require frequent updates to keep pace with antigenic drift of the virus, and the effectiveness, and sometimes the safety, of the vaccine can therefore vary from season to season. Three key populations that the World Health Organization recommends should be prioritized for influenza vaccination are pregnant women, children younger than 5 years of age and the elderly. This review discusses the burden of influenza and the safety and effectiveness profile of influenza vaccines recommended for these groups.

Influenza vaccination discourse in major Canadian news media, 2017-2018

Influenza vaccine uptake is less-than-ideal in many jurisdictions, including Canada. In this study we sought to assess news articles relating to influenza vaccination by major Canadian newspapers during a six-month period relatively congruent to the seasonal influenza outbreak for 2017-2018. We identified 116 unique articles published between August 16, 2017 and February 15, 2018, then developed and applied a coding frame to them. Influenza vaccination was portrayed primarily positively (74.14%), sometimes negatively (14.66%), and occasionally neutrally (11.21%). Articles were most commonly focused on news about the prevalence, or amount of harm/death caused by, the influenza virus (31.03%), or on public announcements primarily concerning influenza vaccination (17.24%). Benefits of influenza vaccination were often stated (59.48%), most commonly including reduction in disease (47.41%) and protection of vulnerable individuals (26.72%). Issues or problems with influenza vaccination were also often stated (55.17%), most commonly relating to low or non-effectiveness of the vaccine (43.10%). Most articles stated that people should get vaccinated (65.52%). Canadian newspaper articles generally support the scientific consensus that influenza vaccination is a highly positive intervention. Nonetheless, a clear picture of the true value of influenza vaccination may sometimes be missing in articles focusing on low effectiveness and lacking any mention of vaccination's positive value. Overall, we can reasonably conclude that, in Canada, misinformation and antivaccination rhetoric are coming primarily from sources other than newspapers.

The safety of inactivated influenza vaccines in pregnancy for birth outcomes: a systematic review

Pregnant women are at increased risk of morbidity and mortality from influenza and are recognized as a priority group for influenza vaccination. Despite this, uptake is often poor and one reason cited for this is concerns about safety. The objective of this study was to perform a systematic review of the safety of inactivated influenza vaccination (IIV) in pregnancy. Studies were included if they were: (i) observational or experimental design; (ii) included a comparator group comprising of unvaccinated pregnant women; (iii) comprised of either seasonal IIV or monovalent H1N1 IIV (including adjuvanted vaccines); and (iv) addressed one of the following outcomes: preterm birth (PTB), small for gestational age (SGA), fetal death (including stillbirth or spontaneous abortion), low birth weight (LBW) or congenital abnormalities. Two reviewers screened abstracts and titles and selected full texts for retrieval. Crude odds ratios were calculated from reported event rates, using binomial standard errors. Adjusted odds ratios, hazard ratios and relative rates were extracted as reported in each paper. After removal of duplicates and full text eligibility assessment, 40 studies remained. The aOR for PTB was 0.87 (0.78–0.96), for LBW 0.82 (0.76–0.89), congenital abnormality 1.03 (0.99–1.07), SGA 0.99 (0.94–1.04) and stillbirth 0.84 (0.65–1.08). This study contributes to the increasing body of safety data for IIV in pregnancy and reports a protective effect on PTB and LBW.

Use of Grading of Recommendations, Assessment, Development, and Evaluation to Combat Fake News: A Case Study of Influenza Vaccination in Pregnancy

BACKGROUND

The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework is a validated evaluation tool used to assess the quality of scientific publications. It helps in enhancing clinicians' decision-making process and supports production of informed healthy policy.

OBJECTIVE

The purpose of this report was two-fold. First, we reviewed the interpretation of observational studies. The second purpose was to share or provide an example using the GRADE criteria.

METHODS

To illustrate the use of the GRADE framework to assess publications, we selected a study evaluating the risk of spontaneous abortion (SAB) after influenza vaccine administration.

RESULTS

Since 2004, the Centers for Disease Control and Prevention and the Advisory Committee on Immunization Practice have recommended influenza vaccination of pregnant women. Previous studies have not found an association between influenza vaccination and SAB. However, in a recent case-control study by Donahue et al, a correlation with SAB in women who received the H1N1 influenza vaccine was identified. For women who received H1N1-containing vaccine in the previous and current influenza season, the adjusted odds ratio (aOR) for SAB was 7.7 (95% CI, 2.2-27.3), while the aOR for women not vaccinated in the previous season but vaccinated in the current season was 1.3 (95% CI, 0.7-2.7).

CONCLUSIONS

Our goal is to enable the readers to critique published literature using appropriate evaluation tools such as GRADE.

Influenza Vaccinations for All Pregnant Women? Better Evidence Is Needed

Pregnant women are a World Health Organization (WHO) priority group for influenza vaccination, but evidence of effectiveness and safety for pregnant women comes from observational studies, which are notoriously prone to confounding by indication and healthy-vaccinee bias. The latter type of bias leads to an overestimation of the effectiveness and safety of the vaccine, which may be what occurs in pregnant women. Indeed, better educated women with healthier behaviors and who seek better medical care may be more adherent to vaccinations recommended by doctors, scientific societies and health authorities. Therefore, it is fundamental to obtain information about vaccine effectiveness and safety from randomized controlled trials (RCTs). Cochrane reviews have identified only one RCT with "low risk of bias". Its results were unclear in terms of maternal, perinatal, and infant deaths and hospitalization, and showed a Number Needed to Vaccine (NNV) of 55 for mothers, with an excess of local adverse effects. A Cochrane review concluded that the inactivated influenza vaccine provides pregnant women with uncertain or very limited protection against influenza-like illnesses and influenza. Some observational studies have suggested possible adverse effects of the inflammation following the vaccination. Consistent with the Cochrane reviewers' conclusions, further trials for influenza vaccines with appropriate study designs and comparison groups are required before promoting universal seasonal influenza vaccinations of pregnant women. Meanwhile, vaccination in second to third trimester should be offered while communicating the uncertainties that still exist, promoting informed choices. Vaccination in the first trimester is debatable and debated. This does not mean leaving women defenseless; many other useful behavioral and environmental measures can reduce infectious disease.

Low-dose Thimerosal (ethyl-mercury) is still used in infants` vaccines: Should we be concerned with this form of exposure?

In developing countries, Thimerosal-containing vaccines (TCV) are the main causes of organic Hg exposure for newborns, neonates, and infants immunized with TCV. This article addresses early-life exposure to this unique organic mercury compound (ethylmercury-EtHg) and the risks of its exposure. English language studies pertaining to Thimerosal/EtHg toxicity and exposure during early life were searched in PubMed; and, those publications judged to be relevant to the topic of this review were selected. The risk from the neurotoxic effects of pre- and post-natal Hg exposures depend, in part, on aggravating or attenuating environmental and/or genetic-associated factors. Health authorities in charge of controlling infectious disease dismiss the toxicology of mercury (immunological and subtle neurological effects as insignificant) related to low-dose Thimerosal. The review addresses the evidence that brings into question the safety of Thimerosal that is still present in vaccines given to pregnant women, infants, and children in developing countries, and recognizes the ethical imperative to extend the use of Thimerosal-free vaccines to developing countries, not just developed countries.

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices-United States, 2018-19 Influenza Season

This report updates the 2017-18 recommendations of the Advisory Committee on Immunization Practices (ACIP) regarding the use of seasonal influenza vaccines in the United States (MMWR Recomm Rep 2017;66[No. RR-2]). Routine annual influenza vaccination is recommended for all persons aged ≥6 months who do not have contraindications. A licensed, recommended, and age-appropriate vaccine should be used. Inactivated influenza vaccines (IIVs), recombinant influenza vaccine (RIV), and live attenuated influenza vaccine (LAIV) are expected to be available for the 2018-19 season. Standard-dose, unadjuvanted, inactivated influenza vaccines will be available in quadrivalent (IIV4) and trivalent (IIV3) formulations. Recombinant influenza vaccine (RIV4) and live attenuated influenza vaccine (LAIV4) will be available in quadrivalent formulations. High-dose inactivated influenza vaccine (HD-IIV3) and adjuvanted inactivated influenza vaccine (aIIV3) will be available in trivalent formulations.Updates to the recommendations described in this report reflect discussions during public meetings of ACIP held on October 25, 2017; February 21, 2018; and June 20, 2018. New and updated information in this report includes the following four items. First, vaccine viruses included in the 2018-19 U.S. trivalent influenza vaccines will be an A/Michigan/45/2015 (H1N1)pdm09-like virus, an A/Singapore/INFIMH-16-0019/2016 (H3N2)-like virus, and a B/Colorado/06/2017-like virus (Victoria lineage). Quadrivalent influenza vaccines will contain these three viruses and an additional influenza B vaccine virus, a B/Phuket/3073/2013-like virus (Yamagata lineage). Second, recommendations for the use of LAIV4 (FluMist Quadrivalent) have been updated. Following two seasons (2016-17 and 2017-18) during which ACIP recommended that LAIV4 not be used, for the 2018-19 season, vaccination providers may choose to administer any licensed, age-appropriate influenza vaccine (IIV, RIV4, or LAIV4). LAIV4 is an option for those for whom it is appropriate. Third, persons with a history of egg allergy of any severity may receive any licensed, recommended, and age-appropriate influenza vaccine (IIV, RIV4, or LAIV4). Additional recommendations concerning vaccination of egg-allergic persons are discussed. Finally, information on recent licensures and labeling changes is discussed, including expansion of the age indication for Afluria Quadrivalent (IIV4) from ≥18 years to ≥5 years and expansion of the age indication for Fluarix Quadrivalent (IIV4), previously licensed for ≥3 years, to ≥6 months.This report focuses on the recommendations for use of vaccines for the prevention and control of influenza during the 2018-19 season in the United States. A Background Document containing further information and a brief summary of these recommendations are available at https://www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/flu.html.These recommendations apply to U.S.-licensed influenza vaccines used within Food and Drug Administration-licensed indications. Updates and other information are available at CDC's influenza website (https://www.cdc.gov/flu). Vaccination and health care providers should check CDC's influenza website periodically for additional information.

What Is New in Maternal Immunization?: Best Articles From the Past Year

This month we focus on current research in maternal immunization. Dr. Jamieson discusses four recent publications, which are concluded with a "bottom line" that is a take-home message. A completed reference for each can be found in on this page along with direct links to abstracts.

Declining responsiveness to influenza vaccination with progression of human pregnancy

BACKGROUND

Influenza immunization is universally recommended during pregnancy to protect mothers and their offspring. However, pregnancy-induced shifts in vaccine responsiveness remain poorly defined.

METHODS

Quantitative and qualitative shifts in the serological response to influenza vaccination were evaluated in healthy women throughout the course of pregnancy. Serum was obtained before and after vaccination among 71 pregnant and 67 non-pregnant women during the 2011-12 and 2012-13 influenza seasons. Serum hemagglutination inhibition (HAI) assay was used to investigate anti-influenza antibody responses by comparing pre-vaccine and post-vaccine geometric mean titers (GMTs) between groups for each antigen. IgG1, IgG2, IgG3, and IgG4 anti-influenza titers were also evaluated by enzyme-linked immunosorbent assay (ELISA). Pregnancy induced shifts in HAI titers and levels of each anti-influenza antibody isotype were evaluated using linear regression models.

RESULTS

Post-vaccine GMTs at day 28 were significantly reduced for women vaccinated during pregnancy for A/California (H1N1) in 2011 (p = 0.027), A/Perth (H3N2) in 2011 (p = 0.037), and B/Wisconsin in 2012 (p = 0.039). Vaccine responses progressively declined with the initiation of vaccination later in pregnancy. Anti-H1N1 IgG1, IgG2, and IgG3 titers were reduced in pregnant women compared to non-pregnant controls, and these titers declined with pregnancy progression. The most striking differences were found for anti-H1N1 IgG1, where titers decreased by approximately 7% each week throughout pregnancy.

CONCLUSIONS

HAI responses elicited by immunization were significantly reduced during pregnancy for three different influenza vaccine antigens. Anti-H1N1 IgG1 was significantly lower in pregnant women and decreased throughout the course of pregnancy. Waning serological responsiveness to influenza vaccination with the progression of human pregnancy has important translational implications for when immunization should be optimally administered during pregnancy.

Update From the Advisory Committee on Immunization Practices

The Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts, meets 3 times per year to develop recommendations for vaccine use in the United States. The group has 15 voting members, each of whom is appointed to a 4-year term. ACIP members and Centers for Disease Control and Prevention (CDC) staff discuss the epidemiology of vaccine-preventable diseases and vaccine research, effectiveness, safety data, and clinical trial results. The ACIP met on October 25 and 26, 2017, to discuss herpes zoster vaccine, the child/adolescent and adult vaccination schedules, Japanese encephalitis (JE) epidemiology and vaccines, pneumococcal vaccines, anthrax vaccines and disaster preparedness, hepatitis A outbreaks, influenza surveillance and vaccination coverage, vaccine safety, and considerations for a potential third dose of measles-mumps-rubella (MMR) vaccine to combat ongoing mumps outbreaks. Representatives from the American Academy of Pediatrics (AAP) (Y. A. M. and D. W. K.) and the Pediatric Infectious Diseases Society (S. T. O.) were present as liaisons from their respective organizations to the ACIP.

Maternal immunization: where are we now and how to move forward?

Pregnancy and the postpartum period are associated with elevated risks to both mother and infant from infectious disease. Vaccination of pregnant women, also called maternal immunization, has the potential to protect pregnant women, foetuses and infants from several vaccine-preventable diseases. Maternal immunoglobulin G antibodies are actively transferred through the placenta to provide passive immunity to new-borns during the first months of life, until the time for infant vaccinations or until the period of greatest susceptibility has passed. Currently, inactivated influenza, tetanus, and pertussis vaccines are recommended during pregnancy in many countries, but other vaccines may also be administered to pregnant women when risk factors are present. Several new vaccines with a specific indication for use during pregnancy are under development (e.g. respiratory syncytial virus and group B streptococcus vaccines). Years of experience suggest that maternal immunization against influenza, tetanus or pertussis has an acceptable safety profile, is well tolerated, effective and confers significant benefits to pregnant women and their infants. This review describes the principles of maternal immunization and provides an update of the recent evidence regarding the use and timing of maternal immunization. Finally, the barriers preventing wider vaccination coverage and the current limitations in addressing these are also described ( Supplementary Material ). Key messages Maternal immunization gives pregnant women greater protection against infectious diseases; induces high levels of maternal antibodies that can be transferred to the foetus; and helps protect new-borns during their first months of life, until they are old enough to be vaccinated. Pregnant women and new-borns are more vulnerable to infectious diseases than the overall population; nevertheless, vaccination rates are often low in pregnant women. This review provides an update of the recent evidence regarding the use and timing of maternal immunization and describes the barriers preventing wider vaccination uptake and the current limitations in addressing these.

No. 357-Immunization in Pregnancy

OBJECTIVE

To review the evidence and provide recommendations on immunization in pregnancy.

OUTCOMES

Outcomes evaluated include effectiveness of immunization and risks and benefits for mother and fetus.

EVIDENCE

The Medline and Cochrane databases were searched for articles published up to January 2017 on the topic of immunization in pregnancy.

VALUES

The evidence obtained was reviewed and evaluated by the Infectious Diseases Committee of the SOGC under the leadership of the principal authors, and recommendations were made according to guidelines developed by the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Implementation of the recommendations in this guideline should result in more appropriate immunization of pregnant and breastfeeding women, decreased risk of contraindicated immunization, and better disease prevention.

RECOMMENDATIONS

Who's the Target: Mother or Baby?

Maternal immunization for prevention of morbidity and mortality of pregnant women and their neonates due to infectious diseases is ongoing worldwide. The complexity of vaccine research and development in this population is challenging. Not only do vaccines for pregnant women require evidence of immunogenicity, potency, stability, and limited reactogenicity, they must also provide efficacy in decreasing morbidity for the pregnant woman, her fetus, and the neonate, demonstrate safety or lack of evidence of harm, and offer benefit or potential benefit of vaccination during pregnancy. Since the 19th century, evidence of protective effects of vaccination during pregnancy has been documented. Pandemic influenza and pertussis outbreaks in recent years have affected a paradigm shift in vaccine research and development as well as current policy regarding immunization in pregnancy. Studies of the immune system in pregnant women and neonates have shown that immune changes associated with pregnancy in women do not interfere with maternal vaccine responses, multiple factors are important in transplacental transfer of antibodies, and maternal antibodies are beneficial to neonates. In recent years, guidelines have been developed by expert panels to help design studies for maternal vaccinations and for harmonization of data collection, analysis, and adverse event reporting. Further research into maternal and neonatal immunology, transplacental antibody transfer, and epidemiology of diseases is needed, especially as new vaccines to respiratory syncytial virus, cytomegalovirus, and Group B streptococcus are developed. Maternal vaccinations have the potential to change the epidemiology of infectious diseases in reproductive health and pediatrics and may lead to new clinical applications to improve global maternal and neonatal health.

Value of an in-depth analysis of unpublished data on the safety of influenza vaccines in pregnant women

Background

Unpublished data can sometimes provide valuable information on the safety of biologic products.

Methods

We assessed information potentially available from regulatory authorities, manufacturers, and public health agencies. We explored 4 recently established vaccine registries, reviewed package inserts from 99 influenza vaccines, and contacted vaccine manufacturers and regulatory agencies for data on influenza vaccine safety in pregnant women.

Results

The vaccine registries did not have sufficient data to analyze and there are problems with the quality of the information. The majority of package inserts provided no product-specific safety information for pregnant women, especially in less developed countries. The majority of available data come from reports gathered from passive adverse event reporting systems in the general population and reports of women enrolled in clinical trials of influenza vaccines who became pregnant at various times before or after receiving influenza vaccine. The information was not collected in a systematic manner, there are inconsistencies in the follow up of pregnant women and the available information about pregnancy outcomes. Considerable resources would be needed to systematically identify all of the information, try to obtain missing follow up information, and conduct analyses. There would be substantial limitations to any attempt to conduct a systematic analysis.

Conclusions

The value of trying to analyze unpublished data on the safety of influenza vaccine in pregnancy is limited and would require considerable resources to thoroughly investigate. Expanding efforts to identify and review unpublished data regarding the safety of influenza vaccines in pregnancy is not likely to produce information of high scientific value or information that could not be identified from publications and other publically available data.