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ACCEPTABILITY AND WILLINGNESS TO PAY FOR INFLUENZA VACCINATION AMONG HEALTHCARE PROFESSIONALS IN VIETNAM

BACKGROUND: While Vietnam’s Expanded Program on Immunization does not cover influenza vaccines, people must pay out-of-pocket for influenza vaccination. Healthcare professionals have a high risk of contracting influenza, but their vaccination rate is low. OBJECTIVE: To examine the willingness to pay (WTP) for influenza vaccination among healthcare professionals in Vietnam . It also recommends financing sources for influenza vaccination among healthcare professionals and determines possible measures to expand vaccine coverage. METHOD: We interviewed 130 healthcare professionals in a national hospital in Hanoi in July 2021. We used Andersen’s behavioral Model (ABM) as an initial approach. The double-bounded dichotomous-choice questions were used to determine WTP for influenza vaccination among the target group. Collected responses were coded and analysed through IBM SPSS version 20 for descriptive, chi-square analyses. RESULTS: Most of the healthcare professionals who responded to this study were female with 75.4 % of the total 130 respondents. The mean age of participants was 34.08 years old. The average maximum WTP for influenza vaccination services was 357.57 VND (USD 15.3). Most of the participants reported that individuals should pay a part of the cost, and four-fifths reported they believed that the government and medical insurance should subsidize the service (80.8 % and 85.4 %). The Chi-square test showed that there was a significant association between perceived severity and history of influenza vaccination with the WTP, X2(1, N=130) = 4.18, p = 0.04, X2 (1, N=130) = 7.81, p = 0.005, respectively. CONCLUSION: The WTP for influenza vaccination among healthcare professionals was found relatively high. Suggesting that price is not a primary barrier. The government and medical insurance were believed to be the potential agencies for improving


INTRODUCTION
Influenza (flu) is a disease caused by the influenza virus.
When infected with the influenza virus, people will develop fever, cough, sore throat, headache, muscle pain, sheer tiredness, and runny nose. [1] It transmits through droplets from ill people when they cough, sneeze, or talk, so the flu quickly spreads. Most people who get flu will recover within a few days to less than two weeks, but some will develop complications like sinus and ear infection, inflammation of the heart and brain. [1] Influenza virus infections are one of morbidity and mortality burden worldwide. According to the World Health Organization, influenza epidemics cause about 3-5 million severe illness cases and about 290,000 to 650,000 respiratory deaths each year. [2] People of all age groups can infect with the influenza virus. However, some groups have a higher risk for developing severe complications when getting flu, such as children under five years old, adults 65 years and older, adults with chronic health conditions, pregnant women, and health care workers. [2] The highest mortality rates of flu were estimated in sub-Saharan Africa (2.8-16.5 per 100 000 individuals), south-east Asia (3.5-9.2 per 100,000 individuals) [3]. One national survey in Vietnam showed that 22 % of patients presenting with ILI were influenza-positive. [4] Among them, 9,3 % reported as hospitalized, of which 19% were influenza positive. [4] The influenza vaccine is the most effective way of reducing the morbidity and mortality of flu. Vaccination is vital for high-risk groups that are easy to develop severe complications from influenza. Healthcare professionals are responsible for providing health care treatment and advice for patients. It means that they contact directly with their patients and be put in a high-risk environment for getting the influenza virus. However, this population's acceptance and vaccine uptake rate is still low. [5][6][7][8] Some studies have examined factors affecting the acceptability and willingness-to-pay (WTP) for influenza vaccine in several subjects, including the woman of childbearing age in Vietnam. [9]  Andersen's behavioural model of health services use (ABM) [15,16]

TARGET POPULATION
The healthcare professionals currently working in the hospital, over 18 years old, cognitively healthy, were eligible for this study, and the exclusion criteria were refusing to participate. The healthcare professionals in this study were doctors, nurses, technicians, and pharmacists.

MEASURES AND INSTRUMENT
We developed a structured questionnaire as an instrument in this study. First, the questionnaire was written in English; then, it was revised and translated into Vietnamese by a language expert.
The final version of the questionnaire was divided into five sections: The State bank of Vietnam) which was adapted from another study in Vietnam [9]. The researcher asked the participant whether they were willing to pay 200,000 VND for one dose of influenza vaccine. Then, the double bid and half bids were then asked following the "yes" and "no" responses, respectively. Lastly, the participants will be asked an open-ended question about the maximum price they can pay for influenza vaccination.

The fifth section is about participants' thoughts on
the responsibility of individuals, medical insurance, and government in terms of paying for influenza vaccination. They also answered about their expectations in financial support from the medical insurance and government.

PROCEDURES
Before data collection, the researcher asked permission to collect data from the National Hospital for Tropical disease.
Then, the researcher went to the hospital and interviewed the eligible participants based on inclusion and exclusion criteria. The participants were randomly selected based on the list of healthcare professionals in this hospital.

STATISTICAL ANALYSIS
The data were coded and analyzed using IBM Statistical Packages for the Social Sciences (version 20).
Descriptive statistics were calculated to understand the participants' sociodemographic characteristics and the percentage of influenza vaccine uptake and WTP.
Chi-square test of independence was performed in our study to find factors affecting the WTP for influenza vaccination.

ETHICAL APPROVAL
The Institutional Review Board, Institute for Population and Social Research, Mahidol University approved the research protocol, with a certificate of approval number2021/06-136 in July 2021. The researcher explained the objectives of the study with potential risks and benefits for the participants.
All the participants of the respondents were also identified as confidential. Participants were interviewed at the hospital in a private area after giving written consent.

FACTORS AFFECTING WTP FOR INFLUENZA VACCINATION
There was no association between socio-demographic factors such as age, gender, education, occupation, and  Although, our study has some limitations. Firstly, we collected data in only one hospital; therefore, the findings are a weak generalization. Secondly, the cross-sectional design makes it difficult to explain the causality between the independent variables and the WTP. However, we enhanced the study's validity by randomly selecting the participants and training the researchers' team to highquality data collection.

CONCLUSION
This study reveals low vaccine uptake, high acceptability, and a high amount of WTP for influenza vaccination among healthcare professionals in Vietnam. It suggests that price is not a primary barrier, and expanding the immunization program to healthcare professionals would be much appreciated. Four-fifths of participants expected the government and medical insurance subsidies, so financing support up to 75% of the vaccine's price from these sources could improve the vaccine uptake rate of a healthcare professional and public at large. In addition, the training and educational program inside or outside the hospital can raise healthcare professionals' awareness about flu and change their practices related to influenza vaccination.

DECLARATION OF COMPETING OF INTEREST
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.