4CMenB Vaccination to Prevent Meningococcal B Disease in Vietnam: Expert Review and Opinion.

An advisory board meeting was held with experts in Vietnam (Hanoi, August 2022), to review the evidence on invasive meningococcal disease (IMD) epidemiology, clinical management, and meningococcal vaccines to reach a consensus on recommendations for meningococcal vaccination in Vietnam. IMD is a severe disease, with the highest burden in infants and children. IMD presents as meningitis and/or meningococcemia and can progress extremely rapidly. Almost 90% of deaths in children occur within the first 24 h, and disabling sequelae (e.g., limb amputations and neurological damage) occur in up to 20% of survivors. IMD patients are often hospitalized late, due to mild and nonspecific early symptoms and misdiagnosis. Difficulties related to diagnosis and antibiotic misuse mean that the number of reported IMD cases in Vietnam is likely to be underestimated. Serogroup B IMD is predominant in many regions of the world, including Vietnam, where 82% of IMD cases were due to serogroup B (surveillance data from 2012 to 2021). Four component meningococcal B vaccine (4CMenB) is used in many countries (and is part of the pediatric National Immunization Program in 13 countries), with infant vaccination starting from two months of age, and a 2 + 1 dosing schedule. Experts recommend 4CMenB vaccination as soon as possible in Vietnam, starting from two months of age, with a 2 + 1 dosing schedule, and at least completing one dose before 6 months of age.

A role for immune modulation in achieving functional cure for chronic hepatitis B among current changes in the landscape of new treatments.

INTRODUCTION: Chronic hepatitis B (CHB) is rarely cured using available treatments. Barriers to cure are: 1) persistence of reservoirs of hepatitis B virus (HBV) replication and antigen production (HBV DNA); 2) high burden of viral antigens that promote T cell exhaustion with T cell dysfunction; 3) CHB-induced impairment of immune responses. AREAS COVERED: We discuss options for new therapies that could address one or more of the barriers to functional cure, with particular emphasis on the potential role of immunotherapy. EXPERT OPINION/COMMENTARY: Ideally, a sterilizing cure for CHB would translate into finite therapies that result in loss of HBV surface antigen and eradication of HBV DNA. Restoration of a functional adaptive immune response, a key facet of successful CHB treatment, remains elusive. Numerous strategies targeting the high viral DNA and antigen burden and aiming to restore the host immune responses will enter clinical development in coming years. Most patients are likely to require combinations of several drugs, personalized according to virologic and disease characteristics, patient preference, accessibility, and affordability. The management of CHB is a global health priority. Expedited drug development requires collaborations between regulatory agencies, scientists, clinicians, and within the industry to facilitate testing of the best drug combinations.

Chronic hepatitis B virus infection (CHB) is a major cause of liver cirrhosis and liver cancer worldwide. Persons with CHB have a dysfunctional immune response that is not capable of clearing the virus from the liver. Two types of treatment are currently available for individuals with CHB. These treatments can have some impact on reducing the risk of cirrhosis and cancer, but they rarely eliminate the virus, and relapse can occur. There are numerous new treatments, such as new antivirals and immunotherapies, being explored for their ability to restore an effective immune response, although to date, there has been little success in this area. Because of the many ways the hepatitis B virus uses to evade the immune system, it is unlikely that one drug or immunotherapy will be able to reliably silence the infection in significant proportions of patients with CHB. Combination regimens involving direct-acting drugs targeting different stages of the virus life cycle, along with stimulation of antiviral immune response are likely to be needed.

Herpes Zoster Burden of Disease and Clinical Management in Turkey: A Comprehensive Literature Review.

INTRODUCTION: Herpes zoster (HZ), or shingles, is caused by the reactivation of varicella zoster virus (VZV) and typically presents as an acute, painful dermatomal rash, but can lead to long-term, distressing complications such as postherpetic neuralgia (PHN). Increasing trends in HZ cases are evident globally among the aging population; however, reviews investigating the epidemiology and clinical management of HZ in Turkey are lacking. Therefore, a literature review of local studies in Turkey was conducted to identify the data available and identify gaps in the literature. METHODS: Literature searches were carried out in PubMed and local journals to retrieve published articles that reported surveillance data, seroepidemiology, patient outcomes, or clinical management related to HZ or VZV in Turkey until April 30, 2022. Studies included primary data reports, case studies, secondary data reviews, and epidemiological studies in healthy or at-risk populations; HZ was the primary focus of the review. RESULTS: No studies reported VZV or HZ epidemiological data at a national level. One large retrospective study in Istanbul reported that HZ incidence rates significantly increased in adults 18-44 years of age between 2011 and 2019. Four single-center studies reported the proportion of dermatological patients with HZ at 0.43-1.56%. PHN was the most common reported complication, occurring in 8-58.9% of patients with HZ. However, out of 39 identified case reports, HZ ophthalmicus was the most frequently reported complication. Two studies highlighted poor disease awareness and risk perception of HZ among Turkish citizens. CONCLUSION: Overall, there were limited comprehensive epidemiological data on HZ in Turkey. However, the abundance of case studies on HZ complications indicates a strong disease presence and diverse clinical management in Turkey. Further research will be important to understand the impact of HZ, increase disease awareness, and support the introduction of new preventative strategies.

Meningococcal B Immunisation in Adults and Potential Broader Immunisation Strategies: A Narrative Review.

Recombinant vaccines against invasive meningococcal disease due to Neisseria meningitidis serogroup B (MenB) have shown substantial impact in reducing MenB disease in targeted populations. 4CMenB targets four key N. meningitidis protein antigens; human factor H binding protein (fHbp), Neisserial heparin binding antigen (NHBA), Neisseria adhesin A (NadA) and the porin A protein (PorA P1.4), with one or more of these expressed by most pathogenic MenB strains, while MenB-FHbp targets two distinct fHbp variants. While many countries recommend MenB immunisation in adults considered at high risk due to underlying medical conditions or immunosuppression, there are no recommendations for routine use in the general adult population. We reviewed the burden of MenB in adults, where, while incidence rates remain low (and far lower than in young children < 5 years of age at greatest risk), a substantial proportion of MenB cases (20% or more) is now observed in the adult population; evident in Europe, Australia, and in the United States. We also reviewed immunogenicity data in adults from clinical studies conducted during MenB vaccine development and subsequent post-licensure studies. A 2-dose schedule of 4CMenB generates hSBA titres ≥ 1:4 towards all four key vaccine target antigens in up to 98-100% of subjects. For MenB-FHbp, a ≥ fourfold rise in hSBA titres against the four primary representative test strains was observed in 70-95% of recipients following a 3-dose schedule. While this suggests potential benefits for MenB immunisation if used in adult populations, data are limited (especially for adults > 50 years) and key aspects relating to duration of protection remain unclear. Although a broader adult MenB immunisation policy could provide greater protection of the adult population, additional data are required to support policy decision-making.

Meningococcal disease within the Gulf Cooperation Council Countries.

This review reports on the recent epidemiology of invasive meningococcal disease (IMD) within the Gulf Cooperation Council (GCC) Countries (focusing from 2012 onwards), the existing immunization strategies and the potential for IMD resurgence. MenACWY vaccination is now established in infant or adolescent immunization programs in Saudi Arabia, Bahrain, Kuwait, and the United Arab Emirates. At present, GCC Countries do not include MenB immunization. National health surveillance reports indicate a total of 156 IMD cases reported across the GCC Countries between 2012 and 2021; between 30% and 80% of cases were reported in individuals aged ≥15 years. Lack of serogroup data hinders the assessment of vaccine impact and decision-making on additional vaccine introductions (e.g. MenB immunization). Hajj/Umrah pilgrimage and the increasing number of large-scale commercial and social events held in the GCC Countries pose a potential risk for future IMD outbreaks. Immunization policies for such events could be strengthened.

Epidemiology of Varicella Zoster Virus and Herpes Zoster Virus in Gulf Cooperation Council Countries: A Review of the Literature.

INTRODUCTION: The reactivation of varicella zoster virus (VZV) in previously infected individuals can cause herpes zoster (HZ), which is characterized by a localized, painful dermatomal rash. While there is a global trend of increasing HZ cases, there is a lack of research examining the epidemiology of HZ within the Gulf Cooperation Council (GCC) countries. Therefore, we aimed to critically appraise evidence on VZV and HZ epidemiology in the GCC countries and identify gaps in the current literature. METHODS: A literature review was conducted via a comprehensive appraisal of the literature. PubMed and local-language journals were searched to identify articles related to HZ and VZV published up until 31 January 2022, with a sole focus on the GCC countries. Included studies reported on surveillance data, seroepidemiology, and patient outcomes for HZ and VZV, and comprised primary data reports, case series, case reports, narrative and systematic literature reviews, studies reporting HZ incidence or prevalence, and Ministry of Health reports. RESULTS: Thirteen studies were found that reported on VZV seroprevalence in Saudi Arabia, the United Arab Emirates (UAE), and Qatar, ranging from 15.0% to 92.2%, while no data were identified for Bahrain, Kuwait, or Oman. There was very limited country-wide information on the incidence of HZ in GCC countries, and three identified studies reported HZ prevalence as seen in a single clinic, ranging from 0.62% to 2.3%. A single study from Saudi Arabia and government surveillance data reported on the impact of VZV vaccination on VZV infection, though there was no evidence on the impact of VZV vaccination on HZ. CONCLUSION: There is a clear gap in the literature regarding the incidence of HZ infection, and the impacts of HZ and VZV vaccinations in the GCC countries. Further research into the epidemiology of HZ is necessary to inform the implementation of vaccination programs in the GCC countries.

Hepatitis A in the Eastern Mediterranean Region: a comprehensive review.

INTRODUCTION: With 583 million inhabitants, the Eastern Mediterranean Region (EMR) is a worldwide hub for travel, migration, and food trade. However, there is a scarcity of data on the epidemiology of the hepatitis A virus (HAV). METHODS: The MEDLINE and grey literature were systematically searched for HAV epidemiological data relevant to the EMR region published between 1980 and 2020 in English, French, or Arabic. RESULTS: Overall, 123 publications were extracted. The proportion of HAV cases among acute viral hepatitis cases was high. HAV seroprevalence rate ranged from 5.7% to 100.0% and it was decreasing over time while the average age at infection increased. CONCLUSION: In the EMR, HAV remains a significant cause of acute viral hepatitis. The observed endemicity shift will likely increase disease burden as the population ages. Vaccinating children and adopting sanitary measures are still essential to disease prevention; vaccinating at-risk groups might reduce disease burden even further.

What is the context?Hepatitis A is a viral liver disease caused by the hepatitis A virus.It is generally transmitted by ingestion of contaminated food or water or through contact with an infected person.Disease severity increases with age. Children under 6 years of age are usually asymptomatic, while adults are the most affected.Limited information exists on the number of cases and transmission of hepatitis A in the Eastern Mediterranean region, which includes 21 countries and Palestine, as defined by the World Health Organization.What is new?We performed a literature review to summarize data on hepatitis A disease in the Eastern Mediterranean region over the last 40 years (1980-2020). As information for many countries is scarce or outdated, most of the data is from Egypt, Iran and Saudi Arabia.We found that: Hepatitis A virus is the most common cause of acute viral hepatitis.Hepatitis A exposure varied according to the country's income level.Low- and middle-income countries showed a universal immunity to hepatitis A virus, although this is not the case anymore.What is the impact?Hepatitis A infections have decreased worldwide. Lower exposure to the virus has led to an increase in the susceptible population (including adolescent and adults).Hepatitis A vaccination for children and high-risk groups such travelers should be considered in the Eastern Mediterranean region.

Meningococcal Disease and Immunization Activities in Hajj and Umrah Pilgrimage: a review.

Invasive meningococcal disease (IMD) outbreaks associated with Hajj and Umrah pilgrimage events in the Kingdom of Saudi Arabia (KSA) are well recognized. Past outbreaks have been associated with substantial intercontinental spread of specific Neisseria meningitidis serogroups. The emergence of meningococcal serogroup W (MenW) was a global concern following the 2000/2001 Hajj outbreaks. Broader compulsory meningococcal serogroups A, C, W and Y (MenACWY) immunization strategies for pilgrims were introduced in response to these events and led to substantial declines in IMD cases associated with these mass gatherings. However, there remains potential for future outbreaks either within KSA during the Hajj or in local populations via pilgrim meningococcal transmission on their return. While the annual Hajj involves pilgrims from over 185 countries, two-thirds of these arrive from 13 countries, chiefly from across South-East Asia, the Middle East and North African (MENA) regions; for which we review the relevant epidemiology of IMD and meningococcal carriage. While disease surveillance is limited and data are often lacking, MenB is an important serogroup associated with IMD and carriage in a number of countries. Available literature suggests that most pilgrims receive polysaccharide MenACWY vaccines (which do not impact carriage and onward transmission) and incomplete compliance with visa/entry immunization regulations is reported. Existing preventative approaches for visiting pilgrims require continued oversight. More complete compliance and switching to the conjugated MenACWY vaccine can provide more robust and broader protection for pilgrims. Additional immunization options could also be considered.

A study on the adaptation of the HIV/AIDS-related Stigma Scale into Turkish.

PURPOSE: This study aims to test the validity and reliability of the Turkish version of the HIV/AIDS-related Stigma Scale. DESIGN AND METHODS: The study has a methodological design. The sample included a total of 428 participants. of the participants, 198 were HIV/AIDS patients, 230 were HIV-negative individuals. The data were analyzed using the Exploratory and Confirmatory Factor Analysis. FINDINGS: The Turkish version of the HIV/AIDS-related Stigma Scale was found to be valid and reliable for the Turkish society. Cronbach's α was 0.93 for the community perspectives subscale and 0.89 for the patient perspectives subscale, and all the model fit indices were acceptable. PRACTICE IMPLICATIONS: The level of stigmatization revealed by the scale helps gain an insight into the community and patient perspectives on HIV/AIDS.

Impact of COVID-19 pandemic on routine immunization.

The current COVID-19 global pandemic continues to impact healthcare services beyond those directly related to the management of SARS-CoV-2 transmission and disease. We reviewed the published literature to assess the pandemic impact on existing global immunization activities and how the impact may be addressed. Widespread global disruption in routine childhood immunization has impacted a majority of regions and countries, especially in the initial pandemic phases. While data indicate subsequent recovery in immunization rates, a substantial number of vulnerable people remain unvaccinated. The downstream impact may be even greater in resource-limited settings and economically poorer populations, and consequently there are growing concerns around the resurgence of vaccine-preventable diseases, particularly measles. Guidance on how to address immunization deficits are available and continue to evolve, emphasizing the importance of maintaining and restoring routine immunization and necessary mass vaccination campaigns during and after pandemics. In this, collaboration between a broad range of stakeholders (governments, industry, healthcare decision-makers and frontline healthcare professionals) and clear communication and engagement with the public can help achieve these goals.Key messagesThe COVID-19 pandemic has a substantial impact on essential immunization activities.Disruption to mass vaccination campaigns increase risk of VPD resurgence.Catch-up campaigns are necessary to limit existing shortfalls in vaccine uptake.Guidance to mitigate these effects continues to evolve.

Seroprevalence and incidence of hepatitis A in Southeast Asia: A systematic review.

BACKGROUND: A previous review on hepatitis A virus (HAV) seroprevalence in 2005 categorized Southeast Asia as a low HAV endemicity region. In 2010, the World Health Organization modified this from low to low/medium endemicity, pointing out that these estimates were based on limited evidence. Since then, there has been no attempt to review HAV epidemiology from this region. We conducted a systematic review of literature to collect information on HAV incidence and seroprevalence in select countries in the Southeast Asian region, specifically, The Association of Southeast Asian Nations over the last 20 years. METHODOLOGY: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. From the relevant articles, we extracted data and conducted a risk of bias assessment of individual studies. RESULTS: The search yielded 22 and 13 publications on HAV seroprevalence and incidence, respectively. Overall, our findings point to a very low HAV endemicity profile in Thailand and Singapore and evidence of a shift towards low HAV endemicity in Indonesia, Lao People's Democratic Republic, Malaysia, the Philippines, and Vietnam. Only Singapore, Thailand, Malaysia, and the Philippines have existing HAV disease surveillance and reported incidence rates below 1 per 100,000. Several outbreaks with varying magnitude documented in the region provide insights into the evolving epidemiology of HAV in the region. Risk of bias assessment of studies revealed that the individual studies were of low to medium risk. CONCLUSIONS/SIGNIFICANCE: The available HAV endemicity profiles in Southeast Asian countries, aside from Thailand, are limited and outdated, but suggest an endemicity shift in the region that is not fully documented yet. These findings highlight the need to update information on HAV epidemiology through strengthening of disease surveillance mechanisms to confirm the shift in HAV endemicity in the region.

The Epidemiology of Invasive Meningococcal Disease in the Kingdom of Saudi Arabia: A Narrative Review with Updated Analysis.

Reducing invasive meningococcal disease (IMD) through MenACWY immunization is a critical healthcare strategy in the Kingdom of Saudi Arabia (KSA). Robust IMD surveillance is essential to help assess the need for additional immunization initiatives in target populations. This is particularly important in KSA, where mass gatherings accompanying Hajj/Umrah pilgrimages have been associated with IMD outbreaks within the local KSA population, and subsequent intercontinental spread via returning pilgrims. This narrative review of the published literature describes the changing epidemiology of IMD in KSA to provide a perspective on the impact of current immunization strategies and potential gaps. As recent published surveillance data are lacking, we also evaluated publicly reported data from the KSA Ministry of Health (MoH) for 2012-2019 to inform more recent IMD trends. Between 1995 and 2011, national surveillance data indicate that 1103 IMD cases were reported in KSA: 60% in 2000-2001, involving two (mainly MenW) outbreaks involving KSA citizens/residents and pilgrims focused in Mecca and Medina. Across 2002-2011, 184 cases of IMD were reported, with a higher proportion occurring in KSA citizens/residents, and with less focus within pilgrimage centers than apparent in previous years. Our analysis of MoH data found that, between 2012 and 2019, 44 IMD cases were reported, all in KSA citizens/residents, and chiefly in children or infants. No pilgrimage-associated outbreaks have occurred since 2001. Serogroup data were available for 62.5% of all cases for 2002-2011; MenW (40.0%), MenA (35.7%), and MenB (16.5%). Serogroup data for 2012-2019 remain incompletely reported, and the existing surveillance system could be improved, as some element of underestimation/underreporting of IMD may exist. While existing MenACWY immunization strategies for KSA citizens/residents and visiting pilgrims have been successful in reducing IMD due to specific serogroups, disease due to MenB remains a potential risk, and additional immunization strategies should be considered.

Rotavirus vaccines performance: dynamic interdependence of host, pathogen and environment.

INTRODUCTION: As of January 2021, rotavirus vaccination programs have been implemented in 109 countries and their use has resulted in a positive impact on rotavirus-related diarrheal hospitalizations and mortality in children below 5 years of age. Despite these successes, several countries in Africa and Asia where disease burden is high have not yet implemented rotavirus vaccination at all or at a scale sufficient enough to demonstrate impact. This could be, among other reasons, due to poor vaccine coverage and the modest levels of efficacy and effectiveness of the vaccines in these resource-limited settings. AREAS COVERED: We review various factors related to the human host (malnutrition, maternally derived antibodies and breastfeeding, genetic factors, blood group, and co-administration with oral polio vaccine), rotavirus pathogen (force of infection, strain diversity and coinfections), and the environment (related to the human microbiome) which reflect complex and interconnected processes leading to diminished vaccine performance in resource-limited settings. EXPERT OPINION: Addressing the limiting factors for vaccine efficacy is needed but likely to take a long time to be resolved. An immediate solution is to increase the immunization coverage to higher values generating an overall effect of adequate proportion of protected population to reduce the prevalence of rotavirus disease.

PLAIN LANGUAGE SUMMARYWhat is the context?Rotavirus is contagious and causes severe diarrhea in children below 5 years of age. It caused 128,500 deaths and 258 million episodes of diarrhea in 2016.Vaccines protecting children from rotavirus are given orally and have been implemented in 109 countries and used for more than a decade. They considerably decreased the number of hospitalizations and deaths.Several Asian and African countries experience rotavirus infections in large numbers and lag behind in implementing rotavirus vaccination programs.In these countries, rotavirus vaccines only prevent a smaller percentage of severe cases. The reasons for this reduction in vaccination impact are not widely known.What is new?We reviewed the literature to identify the reasons that could explain the differences in vaccination impact worldwide.Factors that might influence the impact of vaccination include Infected children (malnutrition, breastfeeding, blood group, and co-administration with oral polio vaccine);Circulating virus(es) (force of infection, number of new strains, and coinfections with other pathogens) Environment: human microbiome (microorganisms at the surface and in the body; that could be altered by diet, method of childbirth, or hygiene).Why is this important?In summary, rotavirus vaccination has reduced rotavirus-associated hospitalizations and deaths; however, more research is needed to understand the factors influencing the impact of vaccination in order to optimize them. (see Figure 1 ­ Graphical PLS).

A review of the experience of childhood hepatitis A vaccination in Saudi Arabia and Turkey: implications for hepatitis A control and prevention in the Middle East and North African region.

In most countries of the Middle East and Northern African (MENA) region, a high hepatitis A virus (HAV) endemicity has been documented. Few others, such as Saudi Arabia and Turkey, are transitioning from high to intermediate endemicity. There is a paucity of recently published HAV disease burden that could be useful to inform or strengthen relevant national hepatitis A vaccination policy and other prevention strategies in the region. This review summarizes information on HAV epidemiology before and after the implementation of a childhood hepatitis A vaccination program in Saudi Arabia and Turkey. In both countries, a clear shift in the age of first HAV exposure has been documented, with more homogeneous trends across regions in Saudi Arabia compared to Turkey. Utilizing the experience of Saudi Arabia and Turkey with hepatitis A vaccination, countries in the region are encouraged to foster discussions on potential vaccination strategies suitable for their own setting.

Long-Term Persistence of Antibody Response with Two Doses of Inactivated Hepatitis A Vaccine in Children.

INTRODUCTION: Hepatitis A virus infection is more severe in adults than children. Although vaccination can protect adults, current childhood programs cover a large population more successfully. Childhood vaccination is, therefore, a solution to protecting adults if it induces lasting immunity. Fifteen-year protection has been demonstrated in children, but longer-term data are only available for adults. We aimed to predict long term persistence of antibody in children beyond 15 years and assess if immunological mechanisms triggered by vaccination support longer-term protection. METHODS: Long-term clinical studies using hepatitis A (HAV) or A/B vaccines (HAB) containing 720 or 1440 Enzyme-linked immunosorbent assay Units (EU) of hepatitis A virus antigen were identified. Duration of persistence of antibodies and possible protection was determined by descriptively comparing antibody geometric mean concentration (GMC) kinetics, as well as GMC (95% confidence interval) at 15 years post-vaccination across studies. Immunological mechanism studies describing hepatitis A vaccination were identified. RESULTS: One study in children 12-15 years (2-dose HAB 720) and four in adults (2-dose HAV 1440 and 3-dose HAB 720) showed comparable GMC kinetics and per year rates of change up to 15 years. At 15 years, the GMC in children [414.7 mEU/ml (336.9; 510.5)] was in the same range as in adults [range 282.6 (217.6; 367.0) to 550.1 (416.0; 727.4)]. Based on these data, mathematical model predictions from adult studies (showing > 85% protected at 50 years) were deemed likely to also apply to children. Studies identified, both humoral and cell-mediated responses are induced following vaccination. CONCLUSION: Based on comparable antibody data in adults and children up to 15 years, similar longer-term antibody persistence is expected in children with 2-dose inactivated hepatitis A 720 containing vaccine at least up to 50 years. Accordingly, improving routine childhood hepatitis A vaccination coverage could protect against more severe disease in adulthood. Fig. 1 Plain language summary TRIAL REGISTRATION: ClinicalTrials.gov identifiers, NCT00875485, NCT01000324, NCT01037114, NCT00289757, NCT00291876.

Vaccine confidence: the keys to restoring trust.

During the 20th century, the discovery of modern vaccines and ensuing mass vaccination dramatically decreased the incidence of many infectious diseases and in some cases eliminated them. Despite this, we are now witnessing a decrease in vaccine confidence that threatens to reverse the progress made. Considering the different extents of low vaccine confidence in different countries of the world, both developed and developing, we aim to contribute to the discussion of the reasons for this, and to propose some viable scientific solutions to build or help restore vaccine confidence worldwide.

Who and when to vaccinate against influenza.

Known since Hippocrates and of continuing public health importance, influenza remains a major cause of morbidity and mortality worldwide, and large segments of the human population are affected every year. Vaccination is the most effective means of preventing influenza infection. Today, many countries have implemented annual influenza vaccination programs, and there is increasing awareness of the potential societal and health benefits of vaccinating pregnant women, children aged 6 months to 5 years, older adults, and persons with underlying medical conditions that make them vulnerable to serious complications of influenza. In this non-systematic review, we summarize data on influenza epidemiology and influenza vaccine immunogenicity, efficacy/effectiveness, and safety in the main high-risk groups. We also discuss the optimal time to vaccinate and the effect of pre-existing immunity on vaccine response.

Vaccinating pregnant women against influenza needs to be a priority for all countries: An expert commentary.

BACKGROUND: In 2012, the World Health Organization recommended influenza vaccination for all pregnant women worldwide and the prioritisation of pregnant women in national influenza vaccination programmes. Nevertheless, vaccination rates in pregnant women often remain much lower than national targets. OBJECTIVES: To assess the benefits and risks associated with influenza infection and vaccination during pregnancy, and to consider obstacles that work against influenza vaccine uptake during pregnancy. RESULTS: There is strong evidence that maternal and foetal outcomes can be compromised if women develop influenza infections during pregnancy. Influenza vaccines have been administered to millions of pregnant women and have demonstrated benefits in terms of disease prevention in mothers and their infants. There is a consensus amongst several recommending authorities that influenza vaccines may be safely administered during all stages of pregnancy. Healthcare professionals are recognised as the most important influencers of vaccine uptake, being well placed to recommend vaccination and directly address safety concerns. CONCLUSIONS: Despite data supporting the value of influenza vaccination during pregnancy, vaccine uptake remains low globally. Low uptake appears to be largely due to ineffective communication with pregnant women about the risks and benefits of influenza vaccination. A graphical abstract is available online.