The partnership for influenza vaccine introduction (PIVI): Supporting influenza vaccine program development in low and middle-income countries through public-private partnerships

Post-introduction evaluation (PIE) of the seasonal influenza vaccination program in Kyrgyzstan in 2023

Vaccination is an effective preventive strategy against influenza. Kyrgyzstan introduced a comprehensive influenza vaccination program in 2013 and has collaborated with the Task Force for Global Health since 2017 to expand vaccination coverage. In 2023, an influenza vaccine post-introduction evaluation was conducted to identify strengths and weaknesses in the influenza vaccination program and to identify measures for improvement. Site visits were conducted across six regions of the country and interviews were conducted with national, regional and district staff, health facility staff, and individuals from priority populations for influenza vaccination using standardized questionnaires. Two major challenges identified in this evaluation were the inadequate supply of influenza vaccine to cover the priority groups and the low acceptance and uptake of influenza vaccine among pregnant people. These findings are important as they can inform targeted strategies and policy updates to increase influenza vaccine implementation and uptake in Kyrgyzstan.

COVID-19 vaccination implementation in six lower- and middle-income countries: Successes, challenges, and lessons for pandemic preparedness

The COVID-19 pandemic challenged health systems in low- and middle-income countries (LMIC) to rapidly deploy vaccines, target adult populations, and integrate the COVID-19 vaccine into existing vaccination programs. This evaluation examined COVID-19 vaccination implementation and planning experiences of six LMICs. We aimed to identify common strategies and investments contributing to country-level readiness to scale up COVID-19 vaccination and gaps in pandemic preparedness. In-depth interviews were conducted with national COVID-19 vaccination program representatives from Côte d'Ivoire, Kyrgyzstan, Moldova, Pakistan, the Philippines, and Zambia. Interview questions covered activities, barriers, and facilitators related to vaccine integration; planning and financing; digital systems; vaccine infrastructure and delivery; adult immunization; the health workforce; and demand and communications. We used the framework analysis method to establish key themes from the recorded data and categorize our results. Countries with influenza vaccine platforms leveraged these to reach adults with COVID-19 vaccines. Community-based platforms were viewed to be an effective approach to vaccinate prioritized populations. Stand-alone delivery platforms and data systems for COVID-19 vaccination were viewed as inefficient and not cost-effective, and vaccine supply delays and shortages were a major issue. Participants highlighted that integrated planning, management, and financing for vaccination activities facilitated the COVID-19 vaccine roll out, and that National Immunization Technical Advisory Groups filled a gap by providing guidance on prioritizing populations for vaccination. Health workers were viewed as key influencers of vaccine uptake by patients and their vaccination was believed by participants to improve public trust in COVID-19 vaccines. These findings informed the following priority areas for targeted investment and technical support. 1. Improve vaccine procurement and supply. 2. Integrate financing and management of national vaccination programs broadly. 3. Digitize and integrate data systems. 4. Build health workforce capacity. 5. Establish and expand adult and life-course vaccination, including health workers. 6. Address hesitancy and misinformation.

Do Pregnant Persons Want Influenza Vaccines? Knowledge, Attitudes, Perceptions, and Practices Toward Influenza Vaccines in 8 Low- and Middle-Income Countries

BACKGROUND

Vaccination is the most effective way to prevent influenza infection and adverse outcomes; despite global recommendations to vaccinate pregnant persons, access to influenza vaccines remains low. We explored knowledge, attitudes, and practices of pregnant persons to inform actions to improve vaccine uptake.

METHODS

We pooled data from cross-sectional surveys assessing pregnant persons' attitudes toward influenza vaccines in 8 low- and middle-income countries. Countries used standard methods to measure attitudes and intents toward influenza vaccination. We stratified by presence/absence of a national influenza vaccination program, income group, geographic region, and individual-level factors.

RESULTS

Our analysis included 8556 pregnant persons from 8 countries. Most pregnant persons (6323, 74%) were willing to receive influenza vaccine if it was offered for free. Willingness differed by presence of an existing influenza vaccination program; acceptance was higher in countries without programs (2383, 89%) than in those with programs (3940, 67%, P < .001).

CONCLUSIONS

Most pregnant persons in middle-income countries, regardless of influenza vaccination program status, were willing to be vaccinated against influenza if the vaccine was provided free of charge. National investments in influenza vaccination programs present an opportunity to avert illness both in pregnant persons themselves and in their newborn babies.

An evaluation of the National Influenza Vaccination Program in the Republic of Moldova, 2023-2024

During the 2023-2024 influenza season, the Republic of Moldova, a lower-middle income country seeking accession into the European Union, independently financed their influenza vaccine supply transitioning from external support from the Partnership for International Vaccine Initiatives, a collaboration conceived in 2015. As part of this transition, a mixed-methods evaluation was conducted from May 2023 - January 2024 to identify current strengths and weaknesses of the influenza vaccination program. A total of 157 interviews were conducted: one with the National Immunization Program (NIP), six with district health officers, 18 at health facilities, 18 with caregivers/parents, 34 with healthcare workers, 43 with adults with chronic diseases, 19 with pregnant women, and 13 vaccine observation sessions; further five expert interviews with an international organization, the insurance company, senior government officials in public health and within the ministry of health, and those involved with COVID-19 were conducted. The Republic of Moldova's NIP has benefited from decades of experience, internal commitments to progress, and contributions from external partners. Despite this progress, the evaluation recognized four areas for improvement. Recommendations from the evaluation assessment included: 1) develop a national strategy for immunization, including the establishment of national goals in consultation with the national immunization technical advisory group (NITAG); 2) expand immunization communications and advocacy initiatives, particularly to adults and pregnant individuals; 3) leverage trusted patient-doctor relationships and encourage vaccination as a healthcare norm with physician specialists; and 4) conduct operations research to better understand vaccine hesitancy in populations such as pregnant individuals. Additional thematic findings emphasized the importance of ensuring timely receipt of vaccine doses into the country no later than September, as medical providers reported difficulty administering doses when vaccines were delivered after September. Our findings outline ways to further strengthen the Republic of Moldova's self-sustained annual influenza vaccination program.

Healthcare personnel acceptance and recommendations for influenza vaccine in twelve low- and middle-income countries: A pooled analysis from 2018 to 2020

BACKGROUND

Although healthcare personnel (HCP) are targeted for influenza vaccination they typically underutilize vaccines especially in low- and middle-income countries. We explored knowledge, attitudes, and practices of HCP about seasonal influenza vaccines (SIV) to identify factors associated with and modifiable barriers to SIV uptake.

METHODS

We pooled individual-level data from cross-sectional surveys about SIV conducted among health workers in 12 low- and middle- income countries during 2018-2020 (i.e., Albania, Armenia, Cote d'Ivoire, Kenya, Kyrgyzstan, Lao PDR, Lebanon, Morocco, North Macedonia, Tunisia, Tajikistan, and Uganda). Eleven countries used a standard protocol and questionnaire based on the Health Belief Model to measure perceptions of susceptibility and severity of influenza disease, benefits of, barriers to, and motivators for vaccination. We analyzed attitudes and perceptions among HCP, including acceptance of vaccine for themselves and willingness to recommend vaccines to patients, grouped by the presence/absence of a national influenza vaccination program. Models were adjusted for geographic region.

RESULTS

Our analysis included 10,281 HCP from 12 countries representing four of the six World Health Organization regions: African, Eastern Mediterranean, European, and Western Pacific. The sample was distributed across low income (LIC) (3,183, 31 %), lower-middle (LMIC) (4,744, 46 %), and upper-middle income (UMIC) (2,354, 23 %) countries. Half (50 %) of the countries included in the analysis reported SIV use among HCP in both the year of and the year preceding data collection while the remainder had no influenza vaccination program for HCP. Seventy-four percent (6,341) of HCP reported that they would be willing to be vaccinated if the vaccine was provided free of charge. HCP in LICs were willing to pay prices for SIV representing a higher percentage of their country's annual health expenditure per capita (6.26 % [interquartile range, IQR: 3.13-12.52]) compared to HCP in LMICs and UMICs. HCP in countries with no SIV program were also willing to pay a higher percentage for SIV (5.01 % [IQR: 2.24-8.34]) compared to HCP in countries with SIV programs.. Most (85 %) HCP in our analysis would recommend vaccines to their patients, and those who would accept vaccines for themselves were 3 times more likely to recommend vaccines to their patients (OR 3.1 [95 % CI 1·8, 5·2]).

CONCLUSION

Increasing uptake of SIV among HCP can amplify positive impacts of vaccination by increasing the likelihood that HCP recommend vaccines to their patients. Successful strategies to achieve increased uptake of vaccines include clear guidance from health authorities, interventions based on behavior change models, and access to vaccine free-of-charge.

Knowledge, attitudes, and practices (KAP) towards seasonal influenza and influenza vaccine among pregnant women in Kyrgyzstan: A cross-sectional study

Influenza is an acute respiratory disease of global importance due to its pandemic potential. Pregnant women are more susceptible to severe illness and adverse outcomes of influenza, and vaccination is the most effective preventive measure for mother and infant. The coverage rate of influenza immunization in Kyrgyzstan is below national targets, despite the World Health Organization's (WHO) recommendation to prioritize pregnant women for vaccination. This study sought to understand drivers and barriers to influenza vaccine uptake in pregnant women in Kyrgyzstan. A knowledge, attitudes, and practices (KAP) survey was administered from December 2018 to March 2019 to 1,193 pregnant women aged 18 and older attending public health institutions in Kyrgyzstan. Multivariate regression analysis was used to determine the association between variables and outcomes of interest.Nearly half (56.2 %) of the 1,193 participants expressed willingness to be vaccinated during their current pregnancy. Participants with only a high school education had a significantly greater intention for vaccination (95 % CI: 1.4-3.2, p < 0.005) in the multivariate analysis compared to participants with university degrees. Participants with underlying health conditions had a higher intention of being vaccinated (95 % CI: 1.2-1.9, p < 0.005). The main reason for vaccine refusal was the belief that influenza vaccines could have adverse effects on the fetus (28.4 %); belief that vaccines could harm their pregnancy (24.3 %); and concern about vaccine effectiveness (10.6 %).These findings are important as they can inform targeted strategies and policy updates to facilitate influenza vaccine implementation and improve uptake among pregnant women in Kyrgystan, and may support strengthening of national influenza vaccine programs in other countries in Central Asia.

A comparative analysis of knowledge, attitude, and practice (KAP) towards influenza and influenza vaccination among healthcare workers in Kyrgyzstan prior to and during the COVID-19 pandemic

INTRODUCTION

Influenza, a globally significant respiratory illness with pandemic potential, affects around 1 billion individuals annually, leading to increased risk for severe illness and mortality. Despite recommendations from the WHO Strategic Advisory Group of Experts on Immunization (SAGE) and MoH prioritization, influenza vaccination coverage rate among HCWs in Kyrgyzstan remains low, ranging between 16 % and 46 % over the past five years. Understanding the Knowledge, Attitudes, and Practices (KAP) dynamics of HCWs regarding influenza vaccinations, both before and during the COVID-19 pandemic is crucial for refining national strategies and institutional approaches to enhance vaccination coverage rates in this important risk group.

METHOD

This study employed cross sectional investigations aimed at assessing KAPs among HCWs regarding influenza disease and vaccination. Conducted prior to and during the initial phase of the COVID-19 pandemic, the project involved 2400 participants from diverse medical disciplines. EPI Info was utilized to run biostatistical analyses, with descriptive and logistic regression models, to elucidate the dynamics of KAP over time.

RESULTS

The findings indicate that HCWs with over 5 years of experience were more likely to get vaccinated or recommend it to patients (p = 0.000). Low confidence in vaccine effectiveness influenced on recommendations of influenza vaccination in pre-pandemic time, where insufficient (95 %CI 0.08-0.6; p = 0.003) or uncertain assurance in vaccine effectiveness (95 %CI 0.007-0.18; p = 0.000) was a barrier for vaccine promotion during the pandemic. The study underscores to consider mandatory influenza vaccination for HCWs which may impact on likelihood of flu vaccination (p = 0.001). Priority groups for influenza vaccination shifted during the COVID-19 period, emphasizing older adults, individuals with existing conditions, and HCWs, compared to the pre-pandemic focus on HCWs, children, and patients with pre-existing conditions.

CONCLUSION

Our investigation provides valuable insights into HCWs KAP concerning influenza vaccination in Kyrgyzstan, highlighting the need for targeted interventions addressing factors influencing vaccine acceptance. The study suggests policy implications, advocating for the revision of national strategies to strengthen capacity building for medical staff.

A qualitative assessment of influenza vaccine uptake among children in Kenya

Background

Influenza is a significant contributor to acute respiratory infections (ARI), and children < 5 years are at increased risk of severe influenza disease. In Kenya the influenza vaccine is not included in the Kenya Expanded Programme on Immunization (KEPI). To inform roll-out of a national influenza vaccination program, we implemented an influenza vaccine demonstration project in Nakuru and Mombasa counties in Kenya from 2019 to 2021 and set out to establish factors driving influenza vaccine acceptance and hesitancy among caregivers of children aged 6-23 months.

Methods

Using semi-structured questionnaires, we conducted eight focus group discussions among community members and twelve key informant interviews among healthcare workers to elicit both lay and expert opinions. Thematic analysis of the interviews was conducted using the World Health Organization's "3 Cs" model of vaccine hesitancy to determine reasons for acceptance or hesitancy of the influenza vaccine.

Results

The influenza vaccine was well received among community members and healthcare workers though concerns were raised. Vaccine hesitancy was fuelled by misconceptions about reasons for introducing the vaccine (confidence), perceptions that influenza was not a serious disease (complacency) and administrative fees required at some facilities (convenience). Despite the use of various advocacy, communication and social mobilisation strategies targeted at educating the community on the influenza disease and importance of vaccination, there remained a perception of inadequate reach of the sensitization among some community members. Contextual factors such as the COVID-19 pandemic affected uptake, and parents expressed concern over the growing number of vaccines recommended for children.

Conclusion

Despite lingering concerns, caregivers had their children vaccinated indicating that vaccine hesitancy exists, even among those who accepted the vaccine for their children. Efforts targeted at increasing confidence in and reducing misconceptions towards vaccines through effective communication strategies, are likely to lead to increased vaccine uptake.

Predictors of Severity of Influenza-Related Hospitalizations: Results From the Global Influenza Hospital Surveillance Network (GIHSN)

BACKGROUND

The Global Influenza Hospital Surveillance Network (GIHSN) has since 2012 provided patient-level data on severe influenza-like-illnesses from >100 participating clinical sites worldwide based on a core protocol and consistent case definitions.

METHODS

We used multivariable logistic regression to assess the risk of intensive care unit admission, mechanical ventilation, and in-hospital death among hospitalized patients with influenza and explored the role of patient-level covariates and country income level.

RESULTS

The data set included 73 121 patients hospitalized with respiratory illness in 22 countries, including 15 660 with laboratory-confirmed influenza. After adjusting for patient-level covariates we found a 7-fold increase in the risk of influenza-related intensive care unit admission in lower middle-income countries (LMICs), compared with high-income countries (P = .01). The risk of mechanical ventilation and in-hospital death also increased by 4-fold in LMICs, though these differences were not statistically significant. We also find that influenza mortality increased significantly with older age and number of comorbid conditions. Across all severity outcomes studied and after controlling for patient characteristics, infection with influenza A/H1N1pdm09 was more severe than with A/H3N2.

CONCLUSIONS

Our study provides new information on influenza severity in underresourced populations, particularly those in LMICs.

Introducing seasonal influenza vaccine in Bhutan: Country experience and achievements

Bhutan successfully introduced multiple vaccines since the establishment of the Vaccine Preventable Disease Program in 1979. Surveillance and subsequent introduction of influenza vaccination became a public health priority for the Ministry of Health following the influenza A(H1N1)pdm09 pandemic. Sentinel surveillance for influenza in Bhutan began in 2008, and a study of severe acute respiratory infection was conducted in 2017, which found the highest influenza burden in children aged <5 years and adults ≥50 years. Following review of surveillance and burden of disease data, the National Technical Advisory Group presented recommendations to Bhutan's Ministry of Health which approved influenza vaccine introduction for all five high-risk groups in the country. Upon the official launch of the program in June 2018, the Vaccine Preventable Disease Program began planning, budgeting, and procurement processes with technical and financial support from the Partnership for Influenza Vaccine Introduction, the United States Centers for Disease Control and Prevention, the Bhutan Health Trust Fund, and the World Health Organization. Influenza vaccination for high-risk groups was integrated into Bhutan's routine immunization services in all health care facilities beginning in November 2019 and vaccinated all populations in 2020 in response to the COVID-19 pandemic. Coverage levels between 2019 and 2022 were highest in children aged 6-24 months (62.5%-96.9%) and lowest in pregnant women (47.7%-62.5%). Bhutan maintained high coverage levels despite the COVID-19 pandemic by continued provision of influenza vaccine services at health centers during lockdowns, conducting communication and sensitization efforts, and using catch-up campaigns. Bhutan's experience with introducing and scaling up the influenza vaccine program contributed to the country's capacity to rapidly deploy its COVID-19 vaccination program in 2021.

Knowledge, attitudes, and practices toward seasonal influenza vaccination among healthcare workers and pregnant women in Pakistan: A mixed methods approach

Vaccine hesitancy is a significant public health issue globally. We aim to document the barriers toward seasonal influenza vaccine uptake among healthcare workers (HCWs) and pregnant women (PW) in Pakistan. We performed a concurrent mixed methods study in four cities (Karachi, Islamabad, Quetta, and Peshawar) across Pakistan from September to December 2021. The quantitative component consisted of independent cross-sectional surveys for PW and HCWs, and the qualitative component comprised of in-depth interviews (IDIs) and focus group discussions (FGDs) among HCWs. Simple linear regression was used to determine the association of sociodemographic variables with knowledge, attitudes, and practices. Overall, 750 PW and 420 HCWs were enrolled. Among the PW, 44% were willing to receive the vaccine if available free of cost. Only 44% of the HCWs were vaccinated; however, 86% intended to get vaccinated and were willing to recommend the vaccine to their patients. HCWs refused vaccine due to side-effects (65%), cost (57%), and allergies (36%). An education level of secondary school and above was predictive of higher attitude and knowledge scores while having received the COVID-19 vaccine was associated with higher practice scores for both PW and HCWs. Several themes emerged from the interviews: 1) HCWs' knowledge of influenza and its prevention, 2) HCWs' perception of motivators and barriers to influenza vaccine uptake and 3) HCWs' attitudes towrd vaccine promotion. We report low influenza vaccine coverage among HCWs and PW in Pakistan. Educational campaigns addressing misconceptions, and improving affordability and accessibility through government interventions, can improve vaccine uptake.

Influenza Vaccination Implementation in Sri Lanka: A Cost-Effectiveness Analysis

Influenza causes an estimated 3 to 5 million cases of severe illness annually, along with substantial morbidity and mortality, particularly in low- and middle-income countries (LMICs). Currently, Sri Lanka has no influenza vaccination policies and does not offer vaccination within the public healthcare sector. Therefore, we performed a cost-effectiveness analysis of influenza vaccine implementation for the Sri Lankan population. We designed a static Markov model that followed a population cohort of Sri Lankans in three age groups, 0-4, 5-64, and 65+ years, through two potential scenarios: trivalent inactivated vaccination (TIV) and no TIV across twelve-monthly cycles using a governmental perspective at the national level. We also performed probabilistic and one-way sensitivity analyses to identify influential variables and account for uncertainty. The vaccination model arm reduced influenza outcomes by 20,710 cases, 438 hospitalizations, and 20 deaths compared to no vaccination in one year. Universal vaccination became cost-effective at approximately 98.01% of Sri Lanka's 2022 GDP per capita (incremental cost-effectiveness ratio = 874,890.55 Rs/DALY averted; 3624.84 USD/DALY averted). Results were most sensitive to the vaccine coverage in the 5-64-year-old age group, the cost of the influenza vaccine dose in the 5-64-years-old age group, vaccine effectiveness in the under-5-years-old age group, and the vaccine coverage in the under-5-years-old age group. No value for a variable within our estimated ranges resulted in ICERs above Rs. 1,300,000 (USD 5386.15) per DALY adverted. Providing influenza vaccines was considered highly cost-effective compared to no vaccines. However, large-scale national studies with improved data are needed to better inform estimates and determine the impact of vaccination implementation.

Factors associated with receipt of COVID-19 vaccination and SARS-CoV-2 seropositivity among healthcare workers in Albania (February 2021-June 2022): secondary analysis of a prospective cohort study

Background

Healthcare workers (HCWs) have been disproportionally affected by COVID-19. We investigated factors associated with two- and three-dose COVID-19 vaccine uptake and SARS-CoV-2 seropositivity among 1504 HCWs enrolled (19 February-7 May 2021) in a prospective COVID-19 vaccine effectiveness cohort in Albania through a secondary analysis.

Methods

We collected sociodemographic, occupational, health, prior SARS-CoV-2 infection, and COVID-19 vaccination data from all HCWs at enrollment. Vaccination status was assessed weekly through June 2022. A serum sample was collected from all participants at enrollment and tested for anti-spike SARS-CoV-2 antibodies. We analyzed HCWs characteristics and outcomes using multivariable logistic regression.

Findings

By 11 June 2022, 1337 (88.9%) HCWs had received two COVID-19 vaccine doses, of whom 255 (19.1%) received a booster. Factors significantly associated with receiving three doses (adjusted odds ratio (aOR), 95% CIs) were being ≥35 years (35-44 years: 1.76 (1.05-2.97); 45-54 years: 3.11 (1.92-5.05); ≥55 years: 3.38 (2.04-5.59)) and vaccinated against influenza (1.78; 1.20-2.64). Booster dose receipt was lower among females (0.58; 0.41-0.81), previously infected (0.67; 0.48-0.93), nurses and midwives (0.31; 0.22-0.45), and support staff (0.19; 0.11-0.32). Overall 1076 (72%) were SARS-CoV-2 seropositive at enrollment. Nurses and midwifes (1.45; 1.05-2.02), support staff (1.57; 1.03-2.41), and HCWs performing aerosol-generating procedures (AGPs) (1.40; 1.01-1.94) had higher odds of being seropositive, while smokers had reduced odds (0.55; 0.40-0.75).

Interpretation

In a large cohort of Albanian HCWs, COVID-19 vaccine booster dose uptake was very low, particularly among younger, female, and non-physician HCWs, despite evidence demonstrating the added benefit of boosters in preventing infection and severe disease. Reasons behind these disparities should be explored to develop targeted strategies in order to promote uptake in this critical population. SARS-CoV-2 seroprevalence was higher among non-physicians and HCWs performing APGs. A better understanding of the factors contributing to these differences is needed to inform interventions that could reduce infections in the future.

Funding

This study was funded by the Task Force for Global Health (US Centers for Disease Control (CDC) cooperative agreement # NU51IP000873) and the World Health Organization, Regional Office for Europe.

Leveraging International Influenza Surveillance Systems and Programs during the COVID-19 Pandemic

A network of global respiratory disease surveillance systems and partnerships has been built over decades as a direct response to the persistent threat of seasonal, zoonotic, and pandemic influenza. These efforts have been spearheaded by the World Health Organization, country ministries of health, the US Centers for Disease Control and Prevention, nongovernmental organizations, academic groups, and others. During the COVID-19 pandemic, the US Centers for Disease Control and Prevention worked closely with ministries of health in partner countries and the World Health Organization to leverage influenza surveillance systems and programs to respond to SARS-CoV-2 transmission. Countries used existing surveillance systems for severe acute respiratory infection and influenza-like illness, respiratory virus laboratory resources, pandemic influenza preparedness plans, and ongoing population-based influenza studies to track, study, and respond to SARS-CoV-2 infections. The incorporation of COVID-19 surveillance into existing influenza sentinel surveillance systems can support continued global surveillance for respiratory viruses with pandemic potential.

CDC's COVID-19 International Vaccine Implementation and Evaluation Program and Lessons from Earlier Vaccine Introductions

The US Centers for Disease Control and Prevention (CDC) supports international partners in introducing vaccines, including those against SARS-CoV-2 virus. CDC contributes to the development of global technical tools, guidance, and policy for COVID-19 vaccination and has established its COVID-19 International Vaccine Implementation and Evaluation (CIVIE) program. CIVIE supports ministries of health and their partner organizations in developing or strengthening their national capacities for the planning, implementation, and evaluation of COVID-19 vaccination programs. CIVIE's 7 priority areas for country-specific technical assistance are vaccine policy development, program planning, vaccine confidence and demand, data management and use, workforce development, vaccine safety, and evaluation. We discuss CDC's work on global COVID-19 vaccine implementation, including priorities, challenges, opportunities, and applicable lessons learned from prior experiences with Ebola, influenza, and meningococcal serogroup A conjugate vaccine introductions.

Influenza

Annual seasonal influenza epidemics of variable severity caused by influenza A and B virus infections result in substantial disease burden worldwide. Seasonal influenza virus circulation declined markedly in 2020-21 after SARS-CoV-2 emerged but increased in 2021-22. Most people with influenza have abrupt onset of respiratory symptoms and myalgia with or without fever and recover within 1 week, but some can experience severe or fatal complications. Prevention is primarily by annual influenza vaccination, with efforts underway to develop new vaccines with improved effectiveness. Sporadic zoonotic infections with novel influenza A viruses of avian or swine origin continue to pose pandemic threats. In this Seminar, we discuss updates of key influenza issues for clinicians, in particular epidemiology, virology, and pathogenesis, diagnostic testing including multiplex assays that detect influenza viruses and SARS-CoV-2, complications, antiviral treatment, influenza vaccines, infection prevention, and non-pharmaceutical interventions, and highlight gaps in clinical management and priorities for clinical research.

Partnering for rotavirus vaccine introduction in India: A retrospective analysis

BACKGROUND

The pre-existing partner network created in India for the delivery of polio vaccines was initially used to eradicate polio and later on embedded in the health systems network to promote routine immunization and other health interventions efficiently. The experience from this network offered lessons for strengthening the health care systems and provided a well-established network that could be utilized for other vaccine initiatives. It has also been established that successful partnerships between a broad range of stakeholders provide support, strengthen the health system, and accelerate vaccine innovation, introduction, access, logistics, and communication support. However, beyond polio eradication, there have not been too many documented success stories of vaccine introduction, which could be replicated in other new vaccine introductions and allied health initiatives. The authors have reviewed the successful and time-bound introduction of rotavirus vaccine (RVV) in India in the present article.

METHODS

The review was conducted based on a partnership framework which analysed multiple factors-partnership prerequisites, partnership model, partnership process, and partnership performance, thereby providing a comprehensive insight into the successful utilization of partnership networks for rotavirus vaccine introduction under the Universal Immunization Program in India.

RESULTS & CONCLUSION

The review also highlights the role of a lead agency in creating a fertile ground for lush, efficient, and effective partnerships amongst different stakeholders. The already existing RVV partnership framework reviewed by the authors can be successfully utilized for future new vaccine introductions.

Estimating the national burden of hospitalizations for influenza-associated severe acute respiratory infection in the Lao People's Democratic Republic, 2016

Objective

Estimates of the burden of influenza are needed to inform prevention and control activities for seasonal influenza, including to support the development of appropriate vaccination policies. We used sentinel surveillance data on severe acute respiratory infection (SARI) to estimate the burden of influenza-associated hospitalizations in the Lao People's Democratic Republic.

Methods

Using methods developed by the World Health Organization, we combined data from hospital logbook reviews with epidemiological and virological data from influenza surveillance from 1 January to 31 December 2016 in defined catchment areas for two sentinel sites (Champasack and Luang Prabang provincial hospitals) to derive population-based estimates of influenza-associated SARI hospitalization rates. Hospitalization rates by age group were then applied to national age-specific population estimates using 2015 census data.

Results

We estimated the overall influenza-associated SARI hospitalization rate to be 48/100 000 population (95% confidence interval [CI]: 44–51) or 3097 admissions (95% CI: 2881–3313). SARI hospitalization rates were estimated to be as low as 40/100 000 population (95% CI: 37–43) and as high as 92/100 000 population (95% CI: 87–98) after accounting for SARI patient underascertainment in hospital logbooks. Influenza-associated SARI hospitalization rates were highest in children aged < 5 years (219; 95% CI: 198–241) and persons aged ³ 65 years (106; 95% CI: 91–121).

Discussion

Our findings have identified age groups at higher risk for influenza-associated SARI hospitalization, which will support policy decisions for influenza prevention and control strategies, including for vaccination. Further work is needed to estimate the burdens of outpatient influenza and influenza in specific high-risk subpopulations.

Using maternal and neonatal data collection systems for coronavirus disease 2019 (COVID-19) vaccines active safety surveillance in low- and middle-income countries: an international modified Delphi study

Background: Given that pregnant women are now included among those for receipt coronavirus disease 2019 (COVID-19) vaccines, it is important to ensure that information systems can be used (or available) for active safety surveillance, especially in low- and middle-income countries (LMICs). The aim of this study was to build consensus about the use of existing maternal and neonatal data collection systems in LMICs for COVID-19 vaccines active safety surveillance, a basic set of variables, and the suitability and feasibility of including pregnant women and LMIC research networks in COVID-19 vaccines pre-licensure activities. Methods: A three-stage modified Delphi study was conducted over three months in 2020. An international multidisciplinary panel of 16 experts participated. Ratings distributions and consensus were assessed, and ratings' rationale was analyzed. Results: The panel recommended using maternal and neonatal data collection systems for active safety surveillance in LMICs (median 9; disagreement index [DI] -0.92), but there was no consensus (median 6; DI 1.79) on the feasibility of adapting these systems. A basic set of 14 maternal, neonatal, and vaccination-related variables. Out of 16 experts, 11 supported a basic set of 14 maternal, neonatal, and vaccination-related variables for active safety surveillance. Seven experts agreed on a broader set of 26 variables. The inclusion of pregnant women for COVID-19 vaccines research (median 8; DI -0.61) was found appropriate, although there was uncertainty on its feasibility in terms of decision-makers' acceptability (median 7; DI 10.00) and regulatory requirements (median 6; DI 0.51). There was no consensus (median 6; DI 2.35) on the feasibility of including research networks in LMICs for conducting clinical trials amongst pregnant women. Conclusions: Although there was some uncertainty regarding feasibility, experts recommended using maternal and neonatal data collection systems and agreed on a common set of variables for COVID-19 vaccines active safety surveillance in LMICs.

Estimating the number of averted illnesses and deaths as a result of vaccination against an influenza pandemic in nine low- and middle-income countries

BACKGROUND

During the 2009 influenza A(H1N1)pdm09 pandemic, 77 countries received donated monovalent A(H1N1)pdm09 vaccine through the WHO Pandemic Influenza A(H1N1) Vaccine Deployment Initiative. However, 47% did not receive their first shipment until after the first wave of virus circulation, and 8% did not receive their first shipment until after the WHO declared the end of the pandemic. Arguably, these shipments were too late into the pandemic to have a substantial effect on virus transmission or disease burden during the first waves of the pandemic.

OBJECTIVES

In order to evaluate the potential benefits of earlier vaccine availability, we estimated the number of illnesses and deaths that could be averted during a 2009-like influenza pandemic under five different vaccine-availability timing scenarios.

METHODS

We adapted a model originally developed to estimate annual influenza morbidity and mortality burden averted through US seasonal vaccination and ran it for five vaccine availability timing scenarios in nine low- and middle-income countries that received donated vaccine.

RESULTS

Among nine study countries, we estimated that the number of averted cases was 61-216,197 for actual vaccine receipt, increasing to 2,914-283,916 had vaccine been available simultaneously with the United States.

CONCLUSIONS

Earlier delivery of vaccines can reduce influenza case counts during a simulated 2009-like pandemic in some low- and middle-income countries. For others, increasing the number of cases and deaths prevented through vaccination may be dependent on factors other than timely initiation of vaccine administration, such as distribution and administration capacity.

Barriers and activities to implementing or expanding influenza vaccination programs in low- and middle-income countries: A global survey

INTRODUCTION

Despite considerable global burden of influenza, few low- and middle-income countries (LMICs) have national influenza vaccination programs. This report provides a systematic assessment of barriers to and activities that support initiating or expanding influenza vaccination programs from the perspective of in-country public health officials.

METHODS

Public health officials in LMICs were sent a web-based survey to provide information on barriers and activities to initiating, expanding, or maintaining national influenza vaccination programs. The survey primarily included Likert-scale questions asking respondents to rank barriers and activities in five categories.

RESULTS

Of 109 eligible countries, 62% participated. Barriers to influenza vaccination programs included lack of data on cost-effectiveness of influenza vaccination programs (87%) and on influenza disease burden (84%), competing health priorities (80%), lack of public perceived risk from influenza (79%), need for better risk communication tools (77%), lack of financial support for influenza vaccine programs (75%), a requirement to use only WHO-prequalified vaccines (62%), and young children require two vaccine doses (60%). Activities for advancing influenza vaccination programs included educating healthcare workers (97%) and decision-makers (91%) on the benefits of influenza vaccination, better estimates of influenza disease burden (91%) and cost of influenza vaccination programs (89%), simplifying vaccine introduction by focusing on selected high-risk groups (82%), developing tools to prioritize target populations (80%), improving availability of influenza diagnostic testing (79%), and developing collaborations with neighboring countries for vaccine procurement (74%) and regulatory approval (73%). Responses varied by country region and income status.

CONCLUSIONS

Local governments and key international stakeholders can use the results of this survey to improve influenza vaccination programs in LMICs, which is a critical component of global pandemic preparedness for influenza and other pathogens such as coronaviruses. Additionally, strategies to improve global influenza vaccination coverage should be tailored to country income level and geographic location.

Ancillary benefits of seasonal influenza vaccination in middle-income countries

While seasonal influenza vaccines (SIV) remain the best method to prevent influenza-associated illnesses, implementing SIV programs may benefit countries beyond disease reduction, strengthening health systems and national immunization programs, or conversely, introduce new challenges. Few studies have examined perceived impacts of SIV introduction beyond disease reduction on health systems; understanding such impacts will be particularly salient in the context of COVID-19 vaccine introduction. We collected qualitative data from key informants-Partnership for Influenza Vaccine Introduction (PIVI) contacts in six middle-income PIVI vaccine recipient countries-to understand perceptions of ancillary benefits and challenges from SIV implementation. Respondents reported benefits associated with SIV introduction, including improved attitudes to SIV among risk groups (characterized by increased demand) and perceptions that SIV introduction improved relationships with other ministries and collaboration with mass media. Challenges included sustaining investment in SIV programs, as vaccine supply did not always meet coverage goals, and managing SIV campaigns.

Global burden of influenza-associated lower respiratory tract infections and hospitalizations among adults: A systematic review and meta-analysis

BACKGROUND

Influenza illness burden is substantial, particularly among young children, older adults, and those with underlying conditions. Initiatives are underway to develop better global estimates for influenza-associated hospitalizations and deaths. Knowledge gaps remain regarding the role of influenza viruses in severe respiratory disease and hospitalizations among adults, particularly in lower-income settings.

METHODS AND FINDINGS

We aggregated published data from a systematic review and unpublished data from surveillance platforms to generate global meta-analytic estimates for the proportion of acute respiratory hospitalizations associated with influenza viruses among adults. We searched 9 online databases (Medline, Embase, CINAHL, Cochrane Library, Scopus, Global Health, LILACS, WHOLIS, and CNKI; 1 January 1996-31 December 2016) to identify observational studies of influenza-associated hospitalizations in adults, and assessed eligible papers for bias using a simplified Newcastle-Ottawa scale for observational data. We applied meta-analytic proportions to global estimates of lower respiratory infections (LRIs) and hospitalizations from the Global Burden of Disease study in adults ≥20 years and by age groups (20-64 years and ≥65 years) to obtain the number of influenza-associated LRI episodes and hospitalizations for 2016. Data from 63 sources showed that influenza was associated with 14.1% (95% CI 12.1%-16.5%) of acute respiratory hospitalizations among all adults, with no significant differences by age group. The 63 data sources represent published observational studies (n = 28) and unpublished surveillance data (n = 35), from all World Health Organization regions (Africa, n = 8; Americas, n = 11; Eastern Mediterranean, n = 7; Europe, n = 8; Southeast Asia, n = 11; Western Pacific, n = 18). Data quality for published data sources was predominantly moderate or high (75%, n = 56/75). We estimate 32,126,000 (95% CI 20,484,000-46,129,000) influenza-associated LRI episodes and 5,678,000 (95% CI 3,205,000-9,432,000) LRI hospitalizations occur each year among adults. While adults <65 years contribute most influenza-associated LRI hospitalizations and episodes (3,464,000 [95% CI 1,885,000-5,978,000] LRI hospitalizations and 31,087,000 [95% CI 19,987,000-44,444,000] LRI episodes), hospitalization rates were highest in those ≥65 years (437/100,000 person-years [95% CI 265-612/100,000 person-years]). For this analysis, published articles were limited in their inclusion of stratified testing data by year and age group. Lack of information regarding influenza vaccination of the study population was also a limitation across both types of data sources.

CONCLUSIONS

In this meta-analysis, we estimated that influenza viruses are associated with over 5 million hospitalizations worldwide per year. Inclusion of both published and unpublished findings allowed for increased power to generate stratified estimates, and improved representation from lower-income countries. Together, the available data demonstrate the importance of influenza viruses as a cause of severe disease and hospitalizations in younger and older adults worldwide.

Development and deployment of COVID-19 vaccines for those most vulnerable

Development of safe and effective COVID-19 vaccines is a global priority and the best hope for ending the COVID-19 pandemic. Remarkably, in less than 1 year, vaccines have been developed and shown to be efficacious and are already being deployed worldwide. Yet, many challenges remain. Immune senescence and comorbidities in aging populations and immune dysregulation in populations living in low-resource settings may impede vaccine effectiveness. Distribution of vaccines among these populations where vaccine access is historically low remains challenging. In this Review, we address these challenges and provide strategies for ensuring that vaccines are developed and deployed for those most vulnerable.

Active pharmacovigilance of the seasonal trivalent influenza vaccine produced by Instituto Butantan: A prospective cohort study of five target groups

Introduction

Active pharmacovigilance studies are pivotal to better characterize vaccine safety.

Methods

These are multicenter prospective cohort studies to evaluate the safety of the 2017 and 2018 seasonal trivalent influenza vaccines (TIVs) manufactured by Instituto Butantan, by means of active pharmacovigilance practices. Elderly, children, healthcare workers, pregnant women, and women in the puerperium period were invited to participate in the study during the 2017 and 2018 Brazilian national seasonal influenza vaccination campaigns. Following immunization, participants were observed for 30 minutes and they received a participant card to register adverse events information. All safety information registered were checked at a clinical site visit 14 days after immunization and by a telephone contact 42 days after immunization for unsolicited Adverse Events (AE) and Guillain-Barré Syndrome (GBS).

Results

A total of 942 volunteers participated in the two studies: 305 elderly, 109 children, 108 pregnant women, 32 women in the postpartum period, and 388 health workers. Overall, the median number of AR per participant ranged from 1 to 4. The lowest median number of AR per participant was observed among healthcare workers (1 AR per participant) and the highest among pregnant women (4 AR per participant). Overall, local pain (46.6%) was the most frequent solicited local AR. The most frequent systemic ARs were: headache (22.5%) followed by fatigue (16.0%), and malaise (11.0%). The majority of solicited ARs (96%) were mild, Grades 1 or 2), only 3% were Grade 3, and 1% was Grade 4. No serious AEs, including Guillain-Barré Syndrome, were reported up to 42 days postvaccination.

Conclusion

The results from the two studies confirmed that the 2017 and 2018 seasonal trivalent influenza vaccines produced by Instituto Butantan were safe and that active pharmacovigilance studies should be considered, when it is feasible, as an important initiative to monitor vaccine safety in the post-marketing period.

Influenza surveillance capacity improvements in Africa during 2011-2017

Background

Influenza surveillance helps time prevention and control interventions especially where complex seasonal patterns exist. We assessed influenza surveillance sustainability in Africa where influenza activity varies and external funds for surveillance have decreased.

Methods

We surveyed African Network for Influenza Surveillance and Epidemiology (ANISE) countries about 2011‐2017 surveillance system characteristics. Data were summarized with descriptive statistics and analyzed with univariate and multivariable analyses to quantify sustained or expanded influenza surveillance capacity in Africa.

Results

Eighteen (75%) of 24 ANISE members participated in the survey; their cumulative population of 710 751 471 represent 56% of Africa's total population. All 18 countries scored a mean 95% on WHO laboratory quality assurance panels. The number of samples collected from severe acute respiratory infection case‐patients remained consistent between 2011 and 2017 (13 823 vs 13 674 respectively) but decreased by 12% for influenza‐like illness case‐patients (16 210 vs 14 477). Nine (50%) gained capacity to lineage‐type influenza B. The number of countries reporting each week to WHO FluNet increased from 15 (83%) in 2011 to 17 (94%) in 2017.

Conclusions

Despite declines in external surveillance funding, ANISE countries gained additional laboratory testing capacity and continued influenza testing and reporting to WHO. These gains represent important achievements toward sustainable surveillance and epidemic/pandemic preparedness.

The Importance of Vaccinating Children and Pregnant Women against Influenza Virus Infection

Influenza virus infection is responsible for significant morbidity and mortality in the pediatric and pregnant women populations, with deaths frequently caused by severe influenza-associated lower respiratory tract infection and acute respiratory distress syndrome (ARDS). An appropriate immune response requires controlling the viral infection through activation of antiviral defenses, which involves cells of the lung and immune system. High levels of viral infection or high levels of inflammation in the lower airways can contribute to ARDS. Pregnant women and young children, especially those born prematurely, may develop serious complications if infected with influenza virus. Vaccination against influenza will lead to lower infection rates and fewer complications, even if the vaccine is poorly matched to circulating viral strains, with maternal vaccination offering infants protection via antibody transmission through the placenta and breast milk. Despite the health benefits of the influenza vaccine, vaccination rates around the world remain well below targets. Trust in the use of vaccines among the public must be restored in order to increase vaccination rates and decrease the public health burden of influenza.