Cost-effectiveness of seasonal influenza vaccination in pregnant women, healthcare workers and adults >= 60 years of age in Lao People's Democratic Republic

Factors associated with influenza and COVID-19 vaccination among health workers in Lao PDR, 2023

Understanding vaccine uptake and related factors among health care workers is critical to successful vaccination programs. A cross-sectional survey was conducted in central, provincial, district hospitals and health centers among health workers in Lao People's Democratic Republic (PDR) in November 2023 to assess health workers' experience with influenza and COVID-19 vaccination, vaccination uptake, intended uptake, and intention to recommend both vaccinations to patients in the future. Logistic regression was used to identify factors associated with these practices. Among 1228 surveyed health workers in six provinces, 55 % were nurses, assistant nurses, or midwives; 32 % were doctors or assistant doctors; and 14 % had other occupations. Overall, 77 % of respondents were female, and the median age was 34 years (interquartile range 29-42 years). Current influenza vaccination and receipt of COVID-19 booster doses were 70 % (95 % confidence interval [CI]: 62-78 %) and 90 % (95 % CI: 87-92 %), respectively. If vaccines were available for free in the future, approximately 94 % and 92 % of health workers would receive influenza and COVID-19 vaccination, respectively. Nearly all health workers would recommend influenza (98 %) and COVID-19 (95 %) vaccination to their patients. Health workers who had received influenza vaccination prior to the COVID-19 pandemic were more likely to have received current influenza vaccination (adjusted odds ratio [aOR], 95 % CI: 3.7, 2.8-4.9) and to intend to receive influenza vaccination in the future (aOR 2.7, 95 % CI: 1.1-6.8). Health workers who were vaccinated for influenza in the current season were more likely to receive COVID-19 booster doses and to intend to receive future booster doses (aOR, 95 % CI: 2.2, 1.3-3.7 and 2.5, 1.2-5.1, respectively). Intention to recommend influenza vaccination to patients was associated with the intention to recommend COVID-19 vaccination to patients, and vice versa. High acceptance for influenza and COVID-19 vaccination among health workers can support a successful vaccination program in Lao PDR.

Epidemiologic and Virologic Characteristics of Influenza in Lao PDR, 2016-2023

BACKGROUND

Influenza sentinel surveillance in Lao PDR is used to inform seasonal vaccination programs. This analysis reviews epidemiologic and virologic characteristics of influenza virus infection over 8 years, before and after emergence of SARS-CoV-2.

METHODS

Data collected for ILI and SARI surveillance during January 2016 through December 2023 were analyzed from nine hospitals. Respiratory specimens from ILI and SARI cases were tested by reverse transcriptase polymerase chain reaction to determine influenza positivity and subtype and lineage. Aggregate counts of outpatient visits and hospitalizations were collected from hospital logbooks. Epidemiologic trends of influenza activity were described, and the proportional contribution of influenza-associated ILI and SARI to outpatient and inpatient loads was estimated.

RESULTS

Influenza was detected year-round with positivity peaking during September through January and occurring in most years approximately 1 month earlier in the south than the north. After decreasing in 2 years following the emergence of SARS-CoV-2, influenza positivity increased in 2022 and resumed its typical temporal trend. Influenza-associated ILI contribution to outpatient visits was highest among children ages 5-14 years (3.0% of all outpatient visits in 2023), and influenza-associated SARI contribution to inpatient hospitalizations was highest among children ages 2-4 years (2.2% of all hospitalizations in 2023).

CONCLUSIONS

Influenza surveillance in Lao PDR provides clinicians and public health authorities with information on geographic and temporal patterns of influenza transmission. Influenza surveillance data support current vaccination timing and recommendations to vaccinate certain populations, especially young children.

Cost-effectiveness of seasonal influenza vaccination in WHO-defined high-risk populations in Bangladesh

Background

Bangladesh carries a substantial health and economic burden of seasonal influenza, particularly among the World Health Organization (WHO)-defined high-risk populations. We implemented a modelling study to determine the cost-effectiveness of influenza vaccination in each of five high-risk groups (pregnant women, children under five years of age, adults with underlying health conditions, older adults (≥60 years), and healthcare personnel) to inform policy decisions on risk group prioritisation for influenza vaccination in Bangladesh.

Methods

We implemented a Markov decision-analytic model to estimate the impact of influenza vaccination for each target risk group. We obtained model inputs from hospital-based influenza surveillance data, unpublished surveys, and published literature (preferentially from studies in Bangladesh, followed by regional and global ones). We used quality-adjusted life years (QALY) as the health outcome of interest. We also estimated incremental cost-effectiveness ratios (ICERs) for each risk group by comparing the costs and QALY of vaccinating compared to not vaccinating each group, where the ICER represents the additional cost needed to achieve one year of additional QALY from a given intervention. We considered a willingness-to-pay threshold (ICER) of less than one gross domestic product (GDP) per capita as highly cost-effective and of one to three times GDP per capita as cost-effective (per WHO standard). For Bangladesh, this threshold ranges between USD 2462 and USD 7386.

Results

The estimated ICERs were USD -99, USD -87, USD -4, USD 792, and USD 229 per QALY gained for healthcare personnel, older adults (≥60), children aged less than five years, adults with comorbid conditions, and pregnant women, respectively. For all risk groups, ICERs were below the WHO willingness-to-pay threshold for Bangladesh. Vaccinating pregnant women and adults with comorbid conditions was highly cost-effective per additional life year gained, while vaccinating healthcare personnel, older adults (≥60), and children under five years were cost-saving per additional life year gained.

Conclusions

Influenza vaccination to all target risk groups in Bangladesh would be either cost-saving or cost-effective, per WHO guidelines of GDP-based thresholds.

Acceptability, cost-effectiveness, and capacity of a facility-based seasonal influenza vaccination among high-risk groups: a study protocol in selected tertiary care hospitals of Bangladesh

BACKGROUND

In Bangladesh, seasonal influenza imposes considerable disease and economic burden, especially for those at high-risk of severe disease. The most successful approach for influenza prevention is the administration of a vaccine. Many poor and middle-income nations, including Bangladesh, do not have a national strategy or program in place for seasonal influenza vaccines, despite the World Health Organization's (WHO) advice to prioritize high-risk populations. Additionally, there is a scarcity of substantial data on the cost-effectiveness of seasonal influenza vaccination in these countries. The aim of our study is to determine acceptability, health beliefs, barriers, and intention of receiving influenza vaccine among high-risk populations, assess the cost-effectiveness of implementing a facility-based seasonal influenza vaccination programme, and investigate the required capacity for a potential seasonal influenza vaccination programme.

METHODS

We will undertake this study following STROBE guidelines. We will conduct the study in inpatient and outpatient departments of three selected tertiary-level hospitals leveraging the ongoing hospital-based influenza surveillance (HBIS) platform. The study population will include the WHO-defined four high-risk groups excluding healthcare workers: children six months to eight years, pregnant women, elderly ≥ 60 years, and adults with chronic diseases. We will collect quantitative data on participants' acceptability, health beliefs, barriers, and vaccination intentions using the health belief model (HBM) from patients meeting the criteria for high-risk populations attending two public tertiary-level hospitals. In one of the two public tertiary-level hospitals, we will arrange an influenza vaccination campaign before the influenza season, where the vaccine will be offered free of cost to high-risk patients, and in the second hospital, vaccination will not be offered. Both the vaccinated and unvaccinated participants will then be followed-up once a month for one year to record any influenza-like illness, hospitalization, and death. Additional data for objective two will be collected from patients with symptoms of influenza-like illness (ILI) and severe acute respiratory infection (SARI) at one public and one private hospital to determine both direct and indirect costs associated with influenza illness. We will estimate the required number of influenza vaccines, safe injections, and total storage volume utilizing secondary data. We will use a deterministic Markov decision-analytic model to estimate the cost-effectiveness of facility-based influenza vaccination in Bangladesh.

DISCUSSION

The results of this study will enable the National Immunization Technical Advisory Group and the Ministry of Health & Family Welfare of Bangladesh to decide what steps to take to develop and implement an influenza vaccination strategy targeting high-risk populations.

TRIAL REGISTRATION

The Clinicaltrials.gov registration number is NCT05996549. The registration for the protocol version 2.0 took place in August 2023, with the initial participant being enrolled in March 2022.

Costs and cost-effectiveness of influenza illness and vaccination in low- and middle-income countries: A systematic review from 2012 to 2022

BACKGROUND

Historically, lack of data on cost-effectiveness of influenza vaccination has been identified as a barrier to vaccine use in low- and middle-income countries. We conducted a systematic review of economic evaluations describing (1) costs of influenza illness; (2) costs of influenza vaccination programs; and (3) vaccination cost-effectiveness from low- and middle-income countries to assess if gaps persist that could hinder global implementation of influenza vaccination programs.

METHODS AND FINDINGS

We performed a systematic search in Medline, Embase, Cochrane Library, CINAHL, and Scopus in January 2022 and October 2023 using a combination of the following key words: "influenza" AND "cost" OR "economic." The search included studies with publication years 2012 through 2022. Studies were eligible if they (1) presented original, peer-reviewed findings on cost of illness, cost of vaccination program, or cost-effectiveness of vaccination for seasonal influenza; and (2) included data for at least 1 low- or middle-income country. We abstracted general study characteristics and data specific to each of the 3 study types. Of 54 included studies, 26 presented data on cost-effectiveness, 24 on cost-of-illness, and 5 on program costs. Represented countries were classified as upper-middle income (UMIC; n = 12), lower-middle income (LMIC; n = 7), and low-income (LIC; n = 3). The most evaluated target groups were children (n = 26 studies), older adults (n = 17), and persons with chronic medical conditions (n = 12); fewer studies evaluated pregnant persons (n = 9), healthcare workers (n = 5), and persons in congregate living settings (n = 1). Costs-of-illness were generally higher in UMICs than in LMICs/LICs; however, the highest national economic burden, as a percent of gross domestic product and national health expenditure, was reported from an LIC. Among studies that evaluated the cost-effectiveness of influenza vaccine introduction, most (88%) interpreted at least 1 scenario per target group as either cost-effective or cost-saving, based on thresholds designated in the study. Key limitations of this work included (1) heterogeneity across included studies; (2) restrictiveness of the inclusion criteria used; and (3) potential for missed influenza burden from use of sentinel surveillance systems.

CONCLUSIONS

The 54 studies identified in this review suggest an increased momentum to generate economic evidence about influenza illness and vaccination from low- and middle-income countries during 2012 to 2022. However, given that we observed substantial heterogeneity, continued evaluation of the economic burden of influenza illness and costs/cost-effectiveness of influenza vaccination, particularly in LICs and among underrepresented target groups (e.g., healthcare workers and pregnant persons), is needed. Use of standardized methodology could facilitate pooling across settings and knowledge sharing to strengthen global influenza vaccination programs.

Cost-effectiveness analysis of seasonal influenza vaccination during pregnancy: A systematic review

BACKGROUND

Seasonal influenza vaccination is clinically important and reduces hospitalization costs for pregnant women. However, is it also a cost-effective intervention?

METHOD

We conducted a systematic search of Medline (via PUBMED), EMBASE, SCOPUS, and Web of Science databases. We included any economic evaluation studies that reported Incremental Cost-Effectiveness Ratios for vaccinating pregnant women against influenza.

RESULT

Out of 927 potentially eligible articles, only 14 full texts met our inclusion criteria. In almost all studies, vaccinating pregnant women was a cost-effective and cost-saving strategy. In one study, it was not cost-effective when the researchers used costs and probabilities related to other groups (healthy adults) due to the lack of data for pregnant women. The main factors influencing the cost-effectiveness of the studies were vaccine efficacy and vaccination cost.

CONCLUSION

Influenza vaccination of pregnant women is a cost-effective intervention. More studies on the cost-effectiveness of this intervention in underdeveloped countries are needed.

Analysis on the intention and influencing factors of free influenza vaccination among the elderly people aged 70 and above in Hangzhou in 2022

Background

Although influenza vaccination is recommended for people aged 70 and above in Hangzhou, and the vaccine is provided free of charge, the elderly influenza vaccination rate is still low. The purpose of this study was to understand the barriers and motivations of older people in deciding to receive free influenza vaccine through questionnaires.

Methods

The method of stratified random sampling was adopted to take samples. A questionnaire survey was conducted among the elderly aged 70 years and above by face-to-face interview or telephone interview.

Results

A total of 11,663 elderly people aged 70-100 years were successfully and effectively interviewed. 85.98% of the respondent were willing to get the influenza shot, 8.91% were unwilling to get the influenza shot, and 5.11% were on vaccine hesitancy. The people of age of 70-79 years old (hesitancy: OR 70~79 = 0.668, 95%CI: 0.571 0.782, Unwilling: OR 70 - 79 = 0.755, 95%CI: 0.622 0.916), primary school degree or below (hesitancy: OR Secondary school degree or above = 1.467, 95%CI: 1.249 1.724, Unwilling: OR Secondary school degree or above = 1.255, 95%CI: 1.028 1.535), remote areas (hesitancy: OR near central urban area = 2.111, 95%CI: 1.604 2.778, OR central urban area = 2.957, 95%CI: 2.255 3.877, Unwilling: OR near central urban area = 1.687, 95%CI: 1.230 2.313. OR centralurbanarea = 2.218, 95%CI: 1.626 3.027), and convenient for movement (hesitancy: OR yes = 0.494, 95%CI: 0.420 0.580, Unwilling: OR yes = 0.585, 95%CI: 0.480 0.713), understanding of the free vaccine policy (hesitancy: OR understand = 0.204, 95%CI: 0.171 0.245, Unwilling: OR understand = 0.164, 95%CI: 0.128 0.210), influenza knowledge level≥ 13 points (hesitancy: OR ≥13points = 0.628, 95%CI: 0.533 0.739, Unwilling: OR ≥13points = 0.538, 95%CI: 0.437 0.662), influenza vaccine knowledge level≥ 12 points (hesitancy: OR ≥12points = 0.422, 95%CI: 0.350 0.508, Unwilling: OR ≥12points = 0.370, 95%CI: 0.290 0.472), and social trust level ≥ 12 points (hesitancy: OR ≥12points = 0.134, 95%CI: 0.112 0.160, Unwilling: OR ≥12points = 0.220, 95%CI: 0.180 0.269) are more willing to receive free influenza vaccine.

Conclusion

The proportion of elderly people aged 70 and above who are willing to receive free influenza vaccine is high in Hangzhou. But the level of knowledge about influenza, vaccine and trust in society is low. The government should continue to improve the elderly's awareness and trust in society through medical staff, family members, television and radio media, and guide the elderly to actively vaccinate against influenza. Effective publicity should be carried out through the above channels to guide the elderly to actively vaccinate against influenza.

Development of a road map to scale up the uptake and utilization of influenza vaccine in 22 countries of Eastern Mediterranean Region

BACKGROUND

The aim of this project was to develop a road map to support countries in Eastern Mediterranean Region in developing and implementing evidence-based seasonal influenza vaccination policy, strengthen influenza vaccination delivery program and address vaccine misperceptions and hesitancy.

METHODS

The road map was developed through consultative meetings with countries' focal points, review of relevant literature and policy documents and analysis of WHO/UNICEF Joint Reporting Form on immunization ((JRF 2015-2020) data. Countries were categorised into three groups, based on the existence of influenza vaccination policy and national regulatory authority, availability of influenza vaccine in the country and number of influenza vaccine doses distributed/ 1000 population. The final road map was shared with representatives of all countries in Eastern Mediterranean Region and other stakeholders during a meeting in September 2021.

RESULT

The goal for next 5 years is to increase access to and use of utilization of seasonal influenza vaccine in Eastern Mediterranean Region to reduce influenza-associated morbidity and mortality among priority groups for vaccination. Countries in the Eastern Mediterranean Region are at different stages of implementation of the influenza vaccination program, so activities are planned under four strategic priority areas based on current situations in countries. The consultative body recommended that some countries should establish a new seasonal influenza vaccination programme and ensure the availability of vaccines, while other countries need to reduce vaccine hesitancy and enhance current seasonal influenza vaccination coverage, particularly in all high-risk groups. Countries are also encouraged to leverage COVID-19 adult vaccination programs to improve seasonal influenza vaccine uptake.

CONCLUSION

This road map was developed through a consultative process to scale up the uptake and utilization of influenza vaccine in all countries of Eastern Mediterranean Region. The road map proposes activities that should be adopted in the local context to develop/ update national policies and programs.

Economic evaluation of seasonal influenza vaccination in elderly and health workers: A systematic review and meta-analysis

BACKGROUND

A number of cost-effectiveness analysis of influenza vaccination have been conducted to estimate value of influenza vaccines in elderly and health workers (HWs). This study aims to summarize cost-effectiveness evidence by pooling the incremental net monetary benefit (INMB) of influenza vaccination.

METHODS

A systematic review was performed in electronic databases from their inceptions to February 2022. Cost-effectiveness studies reporting quality-adjusted life year (QALY), or life year (LY) of influenza vaccination were included. Stratified meta-analyses by population, perspective, country income-level, and herd-effect were performed to pool INMB across studies. The protocol was registered at PROSPERO (CRD42021246746).

FINDINGS

A total of 21 studies were included. Eighteen studies were conducted in elderly, two studies were conducted in HWs, and one study was conducted in both elderly and HWs. According to pre-specified analyses, studies for elderly in high-income economies (countries) (HIEs) and upper-middle income economies (UMIEs) without herd effect could be pooled. For HIEs under a societal perspective, the perspective which identify all relevant costs occurred in the society including direct medical cost, direct non-medical cost and indirect cost, pooled INMB was $217·38 (206·23, 228·53, I² =28.2%), while that for healthcare provider/payer perspective was $0·20 (-11,908·67, 11,909·07, I² = 0.0%). For societal perspective in UMIEs, pooled INMB was $28·39 (-190·65, 133·87, I² = 92.8%). The findings were robust across a series of sensitivity analyses for HIEs. Studies in HWs indicated that influenza vaccination was cost-effective compared to no vaccination or current practice.

INTERPRETATION

Influenza vaccination might be cost-effective for HWs and elderly in HIEs under a societal perspective with relatively small variations among included studies, while there remains limited evidence for healthcare provider/payer perspective or other level of incomes. Further evidence is warranted.

FUNDING

This study was funded by a grant of Immunization, Vaccine and Biologicals department of the World Health Organization. The authors would like to acknowledge the contributions of the US CDC which provided financial support to the development and publication of this report. Grant number US CDC, WHO IVR (U50CK000431).