Benefits of influenza vaccination during pregnancy for pregnant women

COVID-19 and influenza vaccine uptake among pregnant women in national cohorts of England and Wales

Vaccines against COVID-19 and influenza can reduce the adverse outcomes caused by infections during pregnancy, but vaccine uptake among pregnant women has been suboptimal. We examined the COVID-19 and influenza vaccine uptake and disparities in pregnant women during the COVID-19 pandemic to inform vaccination interventions. We used data from the Oxford-Royal College of General Practitioners Research and Surveillance Centre database in England and the Secure Anonymised Information Linkage Databank in Wales. The uptake of at least one dose of vaccine was 40.2% for COVID-19 and 41.8% for influenza among eligible pregnant women. We observed disparities in COVID-19 and influenza vaccine uptake, with socioeconomically deprived and ethnic minority groups showing lower vaccination rates. The suboptimal uptake of COVID-19 and influenza vaccines, especially in those from socioeconomically deprived backgrounds and Black, mixed or other ethnic groups, underscores the necessity for interventions to reduce vaccine hesitancy and enhance acceptance in pregnant women.

Association Between Influenza Vaccination and SARS-CoV-2 Infection

BACKGROUND

Recent data in nonpregnant individuals suggest a protective effect of influenza vaccination against SARS-CoV-2 infection and its severity.

OBJECTIVES

Our primary objective was to evaluate whether influenza vaccination was associated with COVID-19 severity and pregnancy and neonatal outcomes among those infected with SARS-CoV-2. The secondary objective was to examine the association between influenza vaccination and SARS-CoV-2 infection.

STUDY DESIGN

Secondary analysis of a multicenter retrospective cohort of pregnant people who tested positive for SARS-CoV-2 between March and August 2020, and a cohort of random deliveries during the same time period. The associations between 2019 influenza vaccination and the primary outcome of moderate-to-critical COVID-19 as well as maternal and perinatal outcomes were examined among all people who tested positive for SARS-CoV-2 between March and August 2020. The association between 2019 influenza vaccination and having a positive SARS-CoV-2 test was examined among a cohort of individuals who delivered on randomly selected dates between March and August 2020. Univariable and multivariable analyses were performed.

RESULTS

Of 2325 people who tested positive for SARS-CoV-2, 1068 (45.9%) were vaccinated against influenza in 2019. Those who received the influenza vaccine were older, leaner, more likely to have private insurance, and identify as White or Hispanic. They were less likely to smoke tobacco and identify as Black. Overall, 419 (18.0%) had moderate, 193 (8.3%) severe, and 52 (2.2%) critical COVID-19. There was no association between influenza vaccination and moderate-to-critical COVID-19 (29.2% vs. 28.0%, adjusted OR 1.10, 95% CI 0.90-1.34) or adverse maternal and perinatal outcomes among those who tested positive. Of 8152 people who delivered in 2020, 4658 (57.1%) received the influenza vaccine. Prior vaccination was not associated with a difference in the odds of SARS-CoV-2 infection (3.8% vs. 4.2%, adjusted OR 0.94, 95% CI 0.74-1.19).

CONCLUSION

Prior influenza vaccination was not associated with decreased severity of COVID-19 or lower odds of SARS-CoV-2 infection in pregnancy.

Developmental and reproductive safety of Advax-CpG55.2™ adjuvanted COVID-19 and influenza vaccines in mice

SpikoGen® is a recombinant spike protein vaccine against COVID-19 that obtained marketing authorization in the Middle East on October 6th, 2021, becoming the first adjuvanted protein-based COVID-19 vaccine of its type to achieve approval. SpikoGen® vaccine utilizes a unique adjuvant Advax-CpG55.2, which comprises delta inulin and CpG55.2 oligonucleotide, a synthetic human toll-like receptor (TLR)-9 agonist. As part of a safety assessment, developmental and reproductive toxicity (DART) studies were undertaken in mice of Advax-CpG55.2 adjuvanted formulations including SpikoGen®, a H7 hemagglutinin influenza vaccine (rH7HA), the bivalent combination of SpikoGen® and rH7HA, and a next-generation quadrivalent spike protein vaccine. In the first study, vaccines were administered intramuscularly to pregnant dams on gestation days (GD) 6.5 and 12.5, and in the second two doses were given in the pre-mating period with a further two doses during gestation. The doses used in the pregnant mice were 250-1000 times the usual human doses on a weight for weight basis. Strong serum antibody responses with neutralizing activity against the relevant virus were seen in the immunized dams and also at the time of weaning in the sera of their pups, consistent with robust maternal antibody transfer. No adverse effects of any of the vaccine formulations were observed in the immunized dams or their pups. Notably, there were no adverse effects of any of the Advax-CpG55.2 adjuvanted vaccines on female mating performance, fertility, ovarian or uterine parameters, embryo-fetal or postnatal survival, fetal growth, or neurofunctional development. No evidence of antigen interference was observed when SpikoGen® vaccine was mixed and co-administered with influenza hemagglutinin vaccine to pregnant dams. Together with the strong safety profile of SpikoGen® vaccine seen in adults and children in human trials, this DART study data supports the safety of Advax-CpG55.2 adjuvanted COVID-19 and influenza vaccine in women of childbearing potential including during pregnancy.

Developmental and reproductive toxicity of a recombinant protein subunit COVID-19 vaccine (ZF2001) in rats

ZF2001, a protein subunit vaccine against coronavirus disease 2019 (COVID-19), contains recombinant tandem repeat of dimeric receptor-binding domain (RBD) protein of the SARS-CoV-2 spike protein with an aluminium-based adjuvant. During the development of this vaccine, two nonclinical studies were conducted to evaluate female fertility, embryo-fetal development, and postnatal developmental toxicity in Sprague‒Dawley rats according to the ICH S5 (R3) guideline. In Study 1 (embryo-fetal developmental toxicity, EFD), 144 virgin female rats were randomly assigned into four groups and received three doses of vaccine (25 μg or 50 μg RBD protein/dose, containing the aluminium-based adjuvant), the aluminium-based adjuvant or a sodium chloride injection administered intramuscularly on days 21 and 7 prior to mating and on gestation day (GD) 6. In Study 2 (pre- and postnatal developmental toxicity, PPND), ZF2001 at a dose of 25 μg RBD protein/dose or sodium chloride injection was administered intramuscularly to female rats (n = 28 per group) 7 days prior to mating and on GD 6, GD 20 and postnatal day (PND) 10. There were no obvious adverse effects in dams, except for local injection site reactions related to the aluminium-based adjuvant (yellow nodular deposits in the interstitial muscle fibres). There were also no effects of ZF2001 on the mating performance, fertility or reproductive performance of parental females, embryo-fetal development, postnatal survival, growth, physical development, reflex ontogeny, behavioural and neurofunctional development, or reproductive performance of the offspring. The strong immune responses associated with binding and neutralising antibodies were both confirmed in dams and fetuses or offspring in these two studies. These results would support clinical trials or the use of ZF2001 in maternal immunisation campaigns, including those involving women with childbearing potential, regardless of pregnancy status.

Lack of effects on female fertility and prenatal and postnatal offspring development in rats with BNT162b2, a mRNA-based COVID-19 vaccine

BNT162b2 is a vaccine developed to prevent coronavirus disease 2019 (COVID-19). BNT162b2 is a lipid nanoparticle formulated nucleoside-modified messenger RNA (mRNA) encoding the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein locked in its prefusion conformation. A developmental and reproductive toxicity study was conducted in rats according to international regulatory guidelines. The full human BNT162b2 dose of 30 μg mRNA/dose (>300 times the human dose on a mg/kg basis) was administered intramuscularly to 44 female rats 21 and 14 days prior to mating and on gestation days 9 and 20. Half of the rats were subject to cesarean section and full fetal examination at the end of gestation, and the other half were allowed to deliver and were monitored to the end of lactation. A robust neutralizing antibody response was confirmed prior to mating and at the end of gestation and lactation. The presence of neutralizing antibodies was also confirmed in fetuses and offspring. Nonadverse effects, related to the local injection site reaction, were noted in dams as expected from other animal studies and consistent with observations in humans. There were no effects of BNT162b2 on female mating performance, fertility, or any ovarian or uterine parameters nor on embryo-fetal or postnatal survival, growth, physical development or neurofunctional development in the offspring through the end of lactation. Together with the safety profile in nonpregnant people, this ICH-compliant nonclinical safety data supports study of BNT162b2 in women of childbearing potential and pregnant and lactating women.

Use of an Evidence-Based Approach to Improve Influenza Vaccination Uptake in Pregnancy

INTRODUCTION

Influenza can be a significant health threat for any affected individual. Pregnant women are a high-risk population because of the likelihood of developing severe disease. Although the influenza vaccine has been recommended for use by pregnant women since 2004, current vaccination rates among pregnant women are lower than the general population and other high-risk groups.

PROCESS

A quality improvement project was undertaken during the 2019-to-2020 influenza season to increase the uptake of the influenza vaccine by women who were pregnant. The primary objective of the project was to increase the influenza vaccination rate compared with the rate in the previous season. The project had a secondary objective of standardizing documentation of the patient's vaccination status in the health record to capture data for performance measures. Interventions directed at patients, health care providers, and the health care system were simultaneously implemented as recommended by the Community Preventive Services Task Force.

OUTCOMES

Data were collected from 2967 records with 1480 from the 2018-to-2019 season and 1487 from the 2019-to-2020 season. Compared with records from the 2018-to-2019 season, the rate of those associated with a documented influenza vaccine was higher in the 2019-to-2020 season (63% vs 59%; P = .01). The rate of records without vaccination status codes was significantly less in the 2019-to-2020 season compared with the 2018-to-2019 season (14% vs 23%; P < .001).

DISCUSSION

Although interventions were effective in improving influenza vaccination uptake among pregnant women, vaccination rates still remain below the 80% goal set by the US Department of Health and Human Services. Bundled interventions have proven to be more effective than individual interventions, although which interventions are most effective remains unclear.

Pertussis Infections Among Pregnant Women in the United States, 2012–2017

Background

Little is known about pertussis among pregnant women, a population at increased risk for severe morbidity from respiratory infections such as influenza. We used the Centers for Disease Control and Prevention’s Enhanced Pertussis Surveillance (EPS) system to describe pertussis epidemiology among pregnant and nonpregnant women of childbearing age.

Methods

Pertussis cases in women aged 18–44 years with cough onset between 1 January 2012 and 31 December 2017 were identified in 7 EPS states. Surveillance data were collected through patient and provider interviews and immunization registries. Bridged-race, intercensal population data and live birth estimates were used as denominators.

Results

We identified 1582 pertussis cases among women aged 18–44 years; 5.1% (76/1499) of patients with a known pregnancy status were pregnant at cough onset. Of the pregnant patients with complete information, 81.7% (49/60) reported onset during the second or third trimester. The median ages of pregnant and nonpregnant patients were 29.0 and 33.0 years, respectively. Most pregnant and nonpregnant patients were White (78.3% vs. 86.4%, respectively; P = .09) and non-Hispanic (72.6% vs. 77.3%, respectively; P = .35). The average annual incidence of pertussis was 7.7/100000 among pregnancy women and 7/3/100000 among nonpregnant women. Compared to nonpregnant patients, more pregnant patients reported whoop (41.9% vs. 31.3%, respectively), posttussive vomiting (58.1% vs. 47.9%, respectively), and apnea (37.3% vs. 29.0%, respectively); however, these differences were not statistically significant (P values &gt; .05 for all). A similar proportion of pregnant and nonpregnant patients reported ever having received Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine; 31.6% vs. 32.7%, respectively; P = .84).

Conclusions

Our analysis suggests that incidence of pertussis and clinical characteristics of disease are similar among pregnant and nonpregnant women. Continued monitoring is important to further define pertussis epidemiology in pregnant women.

Influenza Vaccine Effectiveness in Preventing Influenza-associated Hospitalizations During Pregnancy: A Multi-country Retrospective Test Negative Design Study, 2010-2016

BACKGROUND

To date, no study has examined influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza-associated hospitalizations during pregnancy.

METHODS

The Pregnancy Influenza Vaccine Effectiveness Network (PREVENT) consisted of public health or healthcare systems with integrated laboratory, medical, and vaccination records in Australia, Canada (Alberta and Ontario), Israel, and the United States (California, Oregon, and Washington). Sites identified pregnant women aged 18 through 50 years whose pregnancies overlapped with local influenza seasons from 2010 through 2016. Administrative data were used to identify hospitalizations with acute respiratory or febrile illness (ARFI) and clinician-ordered real-time reverse transcription polymerase chain reaction (rRT-PCR) testing for influenza viruses. Overall IVE was estimated using the test-negative design and adjusting for site, season, season timing, and high-risk medical conditions.

RESULTS

Among 19450 hospitalizations with an ARFI discharge diagnosis (across 25 site-specific study seasons), only 1030 (6%) of the pregnant women were tested for influenza viruses by rRT-PCR. Approximately half of these women had pneumonia or influenza discharge diagnoses (54%). Influenza A or B virus infections were detected in 598/1030 (58%) of the ARFI hospitalizations with influenza testing. Across sites and seasons, 13% of rRT-PCR-confirmed influenza-positive pregnant women were vaccinated compared with 22% of influenza-negative pregnant women; the adjusted overall IVE was 40% (95% confidence interval = 12%-59%) against influenza-associated hospitalization during pregnancy.

CONCLUSION

Between 2010 and 2016, influenza vaccines offered moderate protection against laboratory-confirmed influenza-associated hospitalizations during pregnancy, which may further inform the benefits of maternal influenza vaccination programs.

Immunobiology of Acute Chorioamnionitis

Acute chorioamnionitis is characterized by neutrophilic infiltration and inflammation at the maternal fetal interface. It is a relatively common complication of pregnancy and can have devastating consequences including preterm labor, maternal infections, fetal infection/inflammation, fetal lung, brain, and gastrointestinal tract injury. In this review, we will discuss current understanding of the pathogenesis, immunobiology, and mechanisms of this condition. Most commonly, acute chorioamnionitis is a result of ascending infection with relatively low-virulence organisms such as the Ureaplasma species. Furthermore, recent vaginal microbiome studies suggest that there is a link between vaginal dysbiosis, vaginal inflammation, and ascending infection. Although less common, microorganisms invading the maternal-fetal interface via hematogenous route (e.g., Zika virus, Cytomegalovirus, and Listeria) can cause placental villitis and severe fetal inflammation and injury. We will provide an overview of the knowledge gleaned from different animal models of acute chorioamnionitis and the role of different immune cells in different maternal-fetal compartments. Lastly, we will discuss how infectious agents can break the maternal tolerance of fetal allograft during pregnancy and highlight the novel future therapeutic approaches.

A Qualitative Study of Views and Experiences of Women and Health Care Professionals about Free Maternal Vaccinations Administered at Community Pharmacies

Background: A policy to extend funding of maternal pregnancy influenza and pertussis vaccinations to community pharmacies could address low pregnancy vaccine uptake. The policy has been implemented in one region in New Zealand. This study explored the views and experiences of women eligible for the vaccines and health care professionals regarding funded maternal vaccinations in pharmacy. Methods: Women in late pregnancy or with an infant, and midwives, pharmacists, and general practice staff were selected purposively and interviewed regarding maternal vaccinations and the new policy, including their awareness and views of the funded vaccinations in pharmacies, and how this policy worked in practice. Enablers and barriers to vaccination by pharmacists were explored. Interviews were transcribed and analysed using a framework approach. Results: Fifty-three interviews were conducted. Most women and health care professionals viewed funded maternal vaccinations in pharmacies positively with respect to increasing awareness and providing delivery options. Many women received messages from pharmacies. Most pharmacies used posters, leaflets and/or verbal explanation to pregnant women to raise awareness of the vaccinations. Not all pharmacies provided these vaccinations, and frontline staff could help to raise awareness. Conclusion: Funded maternal vaccinations in pharmacies are generally well accepted and provide an opportunity to increase uptake and prevent disease.

Influenza-Associated Outcomes Among Pregnant, Postpartum, and Nonpregnant Women of Reproductive Age

BACKGROUND

Pregnant women are prioritized for seasonal influenza vaccination, but the evidence on the risk of influenza during pregnancy that is used to inform these policies is limited.

METHODS

Individual-level administrative data sets and active surveillance data were joined to estimate influenza-associated hospitalization and outpatient visit rates by pregnancy, postpartum, and trimester status.

RESULTS

During 2012-2015, 46 of 260 (17.7%) influenza-confirmed hospitalizations for acute respiratory infection and 13 of 294 (4.4%) influenza-confirmed outpatient visits were among pregnant and postpartum women. Pregnant and postpartum women experienced higher rates of influenza-associated hospitalization than nonpregnant women overall (rate ratio [RR], 3.4; 95% confidence interval [CI], 2.5-4.7) and by trimester (first, 2.5 [95% CI, 1.2-5.4]; second, 3.9 [95% CI, 2.4-6.3]; and third, 4.8 [95% CI, 3.0-7.7]); the RR for the postpartum period was 0.7 (95% CI, 3.0-7.7). Influenza A viruses were associated with an increased risk (RR for 2009 pandemic influenza A[H1N1] virus, 5.3 [95% CI, 3.2-8.7]; RR for influenza A(H3N2) virus, 3.0 [95% CI, 1.8-5.0]), but influenza B virus was not (RR, 1.8; 95% CI, .7-4.6). Influenza-associated hospitalization rates in pregnancy were significantly higher for Māori women (RR, 3.2; 95% CI, 1.3-8.4), compared with women of European or other ethnicity. Similar risks for influenza-confirmed outpatient visits were not observed.

CONCLUSION

Seasonal influenza poses higher risks of hospitalization among pregnant women in all trimesters, compared with nonpregnant women. Hospitalization rates vary by influenza virus type and ethnicity among pregnant women.

Influenza Vaccination, Pregnancy Safety, and Risk of Early Pregnancy Loss

Since 2004, the Centers for Disease Control and Prevention and the American College of Obstetricians and Gynecologists have recommended routine influenza vaccination for all pregnant women in any trimester. Maternal influenza vaccination has been shown to decrease the risk of influenza and its complications among pregnant women and their infants in the first 6 months of life. In a recent article published in Vaccine, Donahue and colleagues reported a possible association between influenza vaccination when given very early in the first trimester and spontaneous abortion. There are limited conclusions that should be drawn from this study given the case-control design as well as the small number of patients included in the subanalysis that is the basis for the report. A prior first-trimester safety study from this group, using a similar study design, had not observed any association with spontaneous abortion, and other reports of first-trimester vaccine safety have not observed an association. The lack of a biologically plausible mechanism for the suggested association between previous influenza vaccination and early pregnancy loss is of concern. The study's reported observation is not definitive and needs be replicated in appropriately designed studies before changing clinical practice. Pregnant women are at high risk for severe influenza-related complications, including death, and health care providers have an obligation to their patients to continue to recommend and provide influenza vaccinations.

Sex differences in vaccine-induced humoral immunity

Vaccines are among the most impactful public health interventions, preventing millions of new infections and deaths annually worldwide. However, emerging data suggest that vaccines may not protect all populations equally. Specifically, studies analyzing variation in vaccine-induced immunity have pointed to the critical impact of genetics, the environment, nutrition, the microbiome, and sex in influencing vaccine responsiveness. The significant contribution of sex to modulating vaccine-induced immunity has gained attention over the last years. Specifically, females typically develop higher antibody responses and experience more adverse events following vaccination than males. This enhanced immune reactogenicity among females is thought to render females more resistant to infectious diseases, but conversely also contribute to higher incidence of autoimmunity among women. Dissection of mechanisms which underlie sex differences in vaccine-induced immunity has implicated hormonal, genetic, and microbiota differences across males and females. This review will highlight the importance of sex-dependent differences in vaccine-induced immunity and specifically will address the role of sex as a modulator of humoral immunity, key to long-term pathogen-specific protection.

Tolerability of trivalent inactivated influenza vaccine among pregnant women, 2015

Background

Thailand recommends influenza vaccination among pregnant women. We conducted a cohort study to determine if the prevalence of adverse events following immunization (AEFIs) with influenza vaccine among Thai pregnant women was similar to that often cited among healthy adults.

Methods

Women who were ≥17 gestational weeks and ≥18 years of age were recruited. Demographic and health history data were collected using structured questionnaires. Women were provided with symptom diary, ruler to measure local reaction(s), and thermometer to measure body temperature. AEFIs were defined as any new symptom/abnormality occurring within four weeks after vaccination. The diaries were abstracted for frequency, duration, and level of discomfort/inconvenience of the AEFIs. Serious adverse events (SAEs) and the likelihood of AEFIs being associated with vaccination were determined using standard definitions.

Results

Among 305 women enrolled between July–November 2015, median age was 29 years. Of these, 223 (73%) were in their third trimester, 271 (89%) had completed secondary school or higher, and 20 (7%) reported ≥1 pre-existing conditions. AEFIs were reported in 134 women (44%; 95% confidence interval [CI] 38–50%). Soreness at the injection site (74, 24%; CI 19–29%), general weakness (50, 16%; CI 12–21%), muscle ache (49, 16%; CI 12–21%), and headache (45, 15%; CI 1–19%) were most common. Of those with AEFIs, 120 (89%) reported symptom/abnormality occurred on day 0 or day 1 following vaccination. Ten women (7%) reported the AEFIs affected daily activities. The AEFIs generally spontaneously resolved within 24 h of onset. There were two vaccine-unrelated SAEs. Of 294 women with complete follow-up, 279 (95%) had term deliveries, 12 (4%) had preterm deliveries, and 3 (1%) had miscarriage or stillbirth.

Conclusion

In our cohort, AEFIs with influenza vaccine occurred with similar frequency to those reported among healthy adults in other studies, and were generally mild and self-limited. No influenza vaccine-associated SAEs were identified.

Immunological Tolerance, Pregnancy, and Preeclampsia: The Roles of Semen Microbes and the Father

Although it is widely considered, in many cases, to involve two separable stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of preeclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its etiology. However, apart from recognizing, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focused on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focusing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the father's semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus (and maybe the placenta) with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of PE. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother via insemination.

Immunologic response to vaccine challenge in pregnant PTPN22 R620W carriers and non-carriers

Objectives

Influenza infection is a significant cause of respiratory morbidity among pregnant women. Seasonal influenza vaccination engages innate immune receptors to promote protective immunity. A coding polymorphism (R620W) in PTPN22 imparts elevated risk for human infection and autoimmune disease, predisposes to diminished innate immune responses, and associates with reduced immunization responses. We sought to quantify the effects of PTPN22-R620W on humoral and cell-mediated immune responses to the inactivated influenza vaccine among healthy pregnant women.

Study Design

Immune responses were measured in healthy pregnant R620W carrier (n = 17) and non-carrier (n = 33) women receiving the 2013 quadrivalent inactivated influenza vaccine (Fluzone). Hemagglutination inhibition assays were performed to quantify neutralizing antibodies; functional influenza-reactive CD4 T cells were quantified by flow cytometry, and influenza-specific CD8 T cells were enumerated with MHC Class I tetramers. Antibody seroconversion data were evaluated by Chi-square analysis, and the Mann-Whitney or Wilcoxon signed-rank tests were applied to T cell response data.

Results

PTPN22 R620W carrier (n = 17) and non-carrier (n = 33) groups did not differ in age, parity, BMI, gestational age at time of vaccine, or history of prior influenza vaccination. After Fluzone exposure, 51.5% of non-carriers met criteria for antibody seroconversion to H1N1 influenza, compared with 23.5% of R620W carriers (p = 0.06). Influenza-reactive CD4 T cells showed modest increase at days 9–15 after vaccination in both R620W carriers and non-carriers (p = 0.02 and p = 0.04, respectively). However, there was no difference in overall response between the two groups (p = 0.6). The vaccine did not result in significant induction of influenza-specific CD8 T cells in either group.

Conclusions

There was no significant difference among healthy pregnant R620W carriers and non-carriers in H1N1 antibody seroconversion rates after influenza vaccination. Studies of larger cohorts will be needed to define the effect of PTPN22 risk allele carriage on antibody and T cell responses to influenza vaccination during pregnancy.

Seasonal influenza vaccination in pregnant women: knowledge, attitudes, and behaviors in Italy

Background

The aims of this study were to assess the knowledge, attitudes, and behaviors towards seasonal influenza and its vaccination among pregnant women.

Methods

A cross-sectional survey was carried out among a sample of women in the second or third trimester of pregnancy in Italy.

Results

The 64.2% of the sample knew that the influenza is more dangerous for pregnant women. Women of older age, Italian, and who had a pregnancy at high-risk were more likely to have this knowledge. This knowledge was lower among women with none, primary or secondary school education. The majority of the respondents considered the vaccine not very useful during pregnancy. Those younger, unmarried, who knew that influenza is more dangerous for pregnant women, who knew that the vaccine could protect them, who reported a higher self-rated health status, and who had received information about influenza and its vaccination were more likely to have a positive attitude toward the usefulness of influenza vaccination in pregnancy. Women with secondary school education and with more than one child revealed a lower perception. Only 9.7% had received the vaccine and 21.4% of those unvaccinated would be willing to receive it. This positive attitude was higher among women with one child, who knew that the vaccine could protect them against the influenza, and who have a positive attitude toward the usefulness of the vaccination during pregnancy.

Conclusions

Health educational programs are needed to improve the knowledge about seasonal influenza and vaccination rate in pregnancy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-2138-2) contains supplementary material, which is available to authorized users.

Guideline for collection, analysis and presentation of safety data in clinical trials of vaccines in pregnant women

Vaccination during pregnancy is increasingly being used as an effective approach for protecting both young infants and their mothers from serious infections. Drawing conclusions from published studies in this area can be difficult because of the inability to compare vaccine trial results across different studies and settings due to the heterogeneity in the definitions of terms used to assess the safety of vaccines in pregnancy and the data collected in such studies. The guidelines proposed in this document have been developed to harmonize safety data collection in all phases of clinical trials of vaccines in pregnant women and apply to data from the mother, fetus and infant. Guidelines on the prioritization of the data to be collected is also provided to allow applicability in various geographic, cultural and resource settings, including high, middle and low-income countries.

Influenza Vaccine Requirements in Pregnant Women

OBJECTIVE

To explore the importance of administering influenza vaccine during pregnancy.

MATERIALS AND METHODS

An internet search for data, study and position papers was done. Medline and Pubmed were the frequently used search engines besides search for WHO and CDC position statements. The keywords used included, influenza vaccine, pregnancy, outcome, safety and trimesters.

RESULTS

Search provided studies that had been conducted in developing nations like Bangladesh as well as developed nations like Norway and England. The WHO and CDC status reports were also accessed and studied.

CONCLUSION

Administration of influenza vaccine is recommended in any trimester of pregnancy, to protect the pregnant woman as well as the newborn child below the age of 6 months from the deleterious effects of influenza. The vaccine is safe and free from side effects.

Optimizing benefits of influenza virus vaccination during pregnancy: potential behavioral risk factors and interventions

Pregnant women and infants are at high risk for complications, hospitalization, and death due to influenza. It is well-established that influenza vaccination during pregnancy reduces rates and severity of illness in women overall. Maternal vaccination also confers antibody protection to infants via both transplacental transfer and breast milk. However, as in the general population, a relatively high proportion of pregnant women and their infants do not achieve protective antibody levels against influenza virus following maternal vaccination. Behavioral factors, particularly maternal weight and stress exposure, may affect initial maternal antibody responses, maintenance of antibody levels over time (i.e., across pregnancy), as well as the efficiency of transplacental antibody transfer to the fetus. Conversely, behavioral interventions including acute exercise and stress reduction can enhance immune protection following vaccination. Such behavioral interventions are particularly appealing in pregnancy because they are safe and non-invasive. The identification of individual risk factors for poor responses to vaccines and the application of appropriate interventions represent important steps towards personalized health care.

Prevention and Control of Influenza Viruses

The 2003–2004 outbreaks of highly pathogenic avian influenza (HPAI) have proven to be disastrous to the regional poultry industry in Asia, and have raised serious worldwide public health apprehension regarding the steps that should be taken to urgently control HPAI. Control measures must be taken based on the principles of biosecurity and disease management and at the same time making public aware of the precautionary measures at the verge of outbreak. Creation of protection and surveillance zones, various vaccination strategies viz. routine, preventive, emergency, mass and targeted vaccination programmes using live, inactivated and recombinant vaccines are the common strategies adopted in different parts of the globe. The new generation vaccines include recombinant vaccines and recombinant fusion vaccine. The pro-poor disease control programmes, giving compensation and subsidies to the farmers along with effective and efficient Veterinary Services forms integral part of control of HPAI. Following biosecurity principles and vaccination forms integral part of control programme against swine and equine influenza as well. Use of neuraminidase (NA) inhibitors (Zanamivir and Oseltamivir) for the treatment of human influenza has been widely accepted worldwide. The threat of increasing resistance of the flu viruses to these antivirals has evoked interest in the development of novel antiviral drugs for influenza virus such as inhibitors of cellular factors and host signalling cascades, cellular miRNAs, siRNA and innate immune peptides (defensins and cathelicidins). Commercial licensed inactivated vaccines for humans against influenza A and B viruses are available consisting of three influenza viruses: influenza type A subtype H3N2, influenza type A subtype H1N1 (seasonal) virus strain and influenza type B virus strain. As per WHO, use of tetravaccine consisting of antigens of influenza virus serotypes H3N2, H1N1, B and H5 is the most promising method to control influenza pandemic. All healthy children in many countries are required to be vaccinated between 6 and 59 months of age. The seasonal vaccines currently used in humans induce strain-specific humoral immunity as the antibodies. Universal influenza virus vaccines containing the relatively conserved ectodomain of M2 (M2e), M1, HA fusion peptide and stalk domains, NA, NP alone or in combination have been developed which have been shown to induce cross-protection. The T cell-based vaccines are another recent experimental approach that has been shown to elicit broad-spectrum heterosubtypic immunity in the host. As far as HPAI is concerned, various pandemic preparedness strategies have been documented.

Influenza vaccination in pregnant women: a systematic review

Objective. To assess the effects of the inactivated influenza virus vaccine on influenza outcomes in pregnant women and their infants. Methods. We performed a systematic review of the literature. We searched for randomized controlled trials and cohort studies in the MEDLINE, Embase, and other relevant databases (inception to September 2013). Two researchers selected studies and extracted the data independently. We used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the quality of the evidence. Results. We included eight studies out of 1,967 retrieved records. Influenza vaccination in pregnant women significantly reduced the incidence of influenza-like illness in mothers and their infants when compared with control groups (high-quality evidence) and reduced the incidence of laboratory-confirmed influenza in infants (moderate-quality evidence). No difference was found with regard to influenza-like illness with fever higher than 38°C (moderate-quality evidence) or upper respiratory infection (very-low-quality evidence) in mothers and infants. Conclusions. Maternal vaccination against influenza was shown to prevent influenza-like illness in women and infants; no differences were found for other outcomes. As the quality of evidence was not high overall, further research is needed to increase confidence and could possibly change these estimates.

Community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) contributes significantly to morbidity and mortality, especially in the elderly. Recent advances aimed at improving outcomes and reducing CAP disease burden are summarized.

RECENT FINDINGS

Emerging data suggests that newer CAP risk stratification indices based on disease severity hold promise in predicting intensive care need. Additional evidence supports a role of procalcitonin and pro-adrenomedullin as biomarkers of disease severity and for guiding antimicrobial therapy. New diagnostic tools have greatly contributed to early diagnosis and better-targeted therapy. There is increasing recognition of the role of coinfections in CAP. In patients with severe disease, therefore, current guidelines advise against monotherapy. Although inclusion of coverage for atypical pathogens in nonsevere CAP has been challenged, evidence suggests that such coverage is beneficial in patients with severe disease. Use of steroids as adjunctive therapy for CAP, however, is associated with complications and prolonged hospitalization. Updated prevention strategies include approval of pneumococcal conjugate vaccine (PCV13) for adults at risk.

SUMMARY

Despite these developments research aimed at further reducing CAP-related morbidity and mortality is required. Increasing global life expectancy is likely to expand the at-risk population; therefore, research directed at CAP prevention in view of changing demography is essential.

Vaccines for low-income countries

Low-income countries typically lag behind industrialised nations, where the introduction of new vaccines is commonly tailored to the pressures of the commercial market. Happily in recent years this paradigm has started to change with the introduction of a univalent meningococcal A conjugate vaccine that is specifically targeted for the prevention of epidemic meningitis in Africa. The declaration of the 2010s as a New Decade of Vaccines, together with Millennium Development Goals 4 and 5, provide a strong mandate for a new approach to the development of vaccines for low-income countries, so that there has never been a more exciting time to work in this field. This review considers the opportunities and challenges of developing these new vaccines in the context of innovations in vaccinology, the need to induce protective immunity in the populations at risk and the requirement for strong partnership between the countries that will use these vaccines and different elements of the vaccine industry.

Translating vaccine policy into action: a report from the Bill & Melinda Gates Foundation Consultation on the prevention of maternal and early infant influenza in resource-limited settings

Immunization of pregnant women against influenza is a promising strategy to protect the mother, fetus, and young infant from influenza-related diseases. The burden of influenza during pregnancy, the vaccine immunogenicity during this period, and the robust influenza vaccine safety database underpin recommendations that all pregnant women receive the vaccine to decrease complications of influenza disease during their pregnancies. Recent data also support maternal immunization for the additional purpose of preventing disease in the infant during the first six months of life. In April 2012, the WHO Strategic Advisory Group of Experts (SAGE) on Immunization recommended revisions to the WHO position paper on influenza vaccines. For the first time, SAGE recommended pregnant women should be made the highest priority for inactivated seasonal influenza vaccination. However, the variable maternal influenza vaccination coverage in countries with pre-existing maternal influenza vaccine recommendations underscores the need to understand and to address the discrepancy between recommendations and implementation success. We present the outcome of a multi-stakeholder expert consultation on inactivated influenza vaccination in pregnancy. The creation and implementation of vaccine policies and regulations require substantial resources and capacity. As with all public health interventions, the existence of perceived and real risks of vaccination will necessitate effective and transparent risk communication. Potential risk allocation and sharing mechanisms should be addressed by governments, vaccine manufacturers, and other stakeholders. In resource-limited settings, vaccine-related issues concerning supply, formulation, regulation, evidence evaluation, distribution, cost-utility, and post-marketing safety surveillance need to be addressed. Lessons can be learned from the Maternal and Neonatal Tetanus Elimination Initiative as well as efforts to increase vaccine coverage among pregnant women during the 2009 influenza pandemic. We conclude with an analysis of data gaps and necessary activities to facilitate implementation of maternal influenza immunization programs in resource-limited settings.

Programmatic and research priorities for improving influenza immunization of pregnant women

Despite evidence regarding the benefits of influenza immunization during pregnancy for both the pregnant woman and her infant, as well as reassuring safety data, influenza vaccination rates in pregnancy have lagged. The 2009 influenza pandemic was accompanied by increased maternal vaccination rates. In this article, we review programmatic and research priorities with regard to overcoming barriers to influenza immunization of pregnant women.