HCWs are the priority group for influenza vaccination in China and abroad; however, the domestic influenza vaccination rate had always been low. The respondents of this study were users of the “Breath Circles” platform, most of whom were respiratory physicians or nurses who were aware of the dangers of respiratory diseases. However, the vaccination rate among them in the 2021/2022 influenza seasons was 35.4%, far lower than that in developed countries in Europe and the United States . This may be related to national policies—China has not included influenza vaccination in the immunization program. Only 19.0% of the respondents reported that their workplace offered free vaccination. In addition, except for mandatory vaccination, no single intervention has been shown to rapidly and substantially increase and sustain vaccination uptake . A study found that voluntary policy-based vaccination rarely achieved and maintained a > 40% influenza vaccination rate in practice . In the United States, a large proportion of hospitals mandate HCWs to receive the influenza vaccine (61.4% in 2017) . The Virginia Mason Medical Center in Seattle, USA, uses influenza vaccination as an employment condition, and in 2005, the implementation of a mandatory vaccination policy increased vaccination coverage among more than 5000 HCWs in the next four influenza seasons by > 98% .
At the same time, the vaccination rate among HCWs during the 2020/2021 and 2021/2022 influenza seasons in this study was lower than that in the 2019/2020 influenza season (67%) but higher than that in the 2018/2019 influenza season (11.6%) . The reason for the higher rate compared to that of the 2018/2019 influenza season may be due to the official statement by the Chinese Health Commission in 2018/2019 encouraging influenza vaccination. This was the first specific guideline for the vaccination of HCWs put forward, requiring medical institutions at all levels to provide free influenza vaccination to HCWs and ensure that all HCWs in high-risk departments are vaccinated. The reason for the lower rate compared to that in the 2019/2020 influenza season is probably because the COVID-19 pandemic reduced access to vaccines. COVID-19 vaccination became the priority at all level medical facilities, and the influenza vaccine cannot be administered at the same time. The decrease in vaccine coverage among HCWs in the 2021/2022 influenza season compared to the 2020/2021 influenza season may be attributed to the COVID-19 vaccination campaign in key populations in China, which started on December 15, 2020 and was expanded to the general population from February 19, 2021 . The utilization of routine immunization resources by COVID-19 has led to the inconvenience of influenza vaccination, given that coadministration of the two vaccines is not allowed. In addition, the free influenza vaccination campaign in most areas were completed by the end of November in previous years, and the majority of people in other regions had been vaccinated by February. Our study, which completed questionnaire response collection before the end of the influenza season, may have slightly underestimated the vaccine coverage. In addition, our research reported on the economic level of those living in the city, engagement in vaccination work, frequent recommendation of respiratory infectious disease-related vaccines to suitable vaccination populations, supportive attitude for all HCWs to be influenza vaccinated, work place requirement, work place free vaccination policies. HCWs were more likely to be vaccinated if the vaccinations were free. Meanwhile, in this study, the two main reasons why HCWs were vaccinated in 2021/2022 were the HCW’s concerns regarding infecting others and contracting influenza themselves, which was consistent with previous studies elsewhere (Italy Belgium Slovenia ), Peru Australia and Singapore ).
Vaccine hesitancy among HCWs is a public health challenge . The main reasons why the HCWs in this study were not vaccinated during the 2021/2022 influenza season included inconvenient vaccination locations, which may be caused by the decreasing number of free influenza vaccination facilities due to the impact of the COVID-19 pandemic since more vaccination facilities have been diverted to COVID-19 vaccination, and access the influenza vaccine has decreased.
However, the COVID-19 pandemic has not subsided, and the low influenza vaccination among rats HCWs may cause problems. The high incidence of influenza may cause HCWs to contract influenza and COVID-19, or other respiratory infectious diseases, resulting in an epidemic of multiple respiratory infectious diseases. In addition, the influenza vaccine also strengthens immunity and reduces the severity of COVID-19 . The WHO noted in the Global Influenza Strategy 2019–2030 that an outbreak of influenza may highlight the burden and severity of annual epidemics on the global population and health systems of countries; seasonal epidemics may highlight the economic burden of direct and indirect costs . A recent study in the United States showed that mandatory influenza vaccination reduced symptom absenteeism rates among policies HCWs as influenza vaccination rates increased . Influenza vaccination also saves countries costs. A review of more than 140 studies showed that the per capita cost of incidences of seasonal influenza ranged from USD 30 to over USD 60, and that the cost-effectiveness ratios for vaccination ranged from USD 10,000/outcome to more than USD 50,000/outcome .
In summary, effective measures should be taken to improve influenza vaccination coverage among HCWs. Our study found that HCWs who were required to be vaccinated by hospitals were more likely to be vaccinated; which is consistent with findings in the United States, where the influenza vaccination rate among HCWs as 92.3% during 2016–2017 , and the highest vaccination rates were recorded among HCWs whose employer required influenza vaccination (96.7%), compared to 45.8% in healthcare facilities where influenza vaccination was not required, promoted, or offered on-site. As free vaccination was most likely the driving factor for promoting influenza vaccination among HCWs, hospitals could formulate free vaccination policies to encourage vaccination. In addition, access to influenza vaccination also needs to be improved through measures such as improving the public health function of hospitals and providing influenza vaccination points in hospitals. On-site vaccination is also an effective measure to improve vaccine coverage. An Italian study found that the introduction of an on-site strategy doubled influenza vaccine coverage in the 2017/18 influenza season compared to the previous season . Technical guidelines for influenza vaccination in China (2021–2022) also recommend increasing the number of primary influenza vaccination points, starting vaccination earlier, extending the duration of vaccination, increasing daily service hours, and encouraging influenza vaccination campaigns for HCWs . In addition, since influenza and COVID-19 vaccines cannot be administered at the same time, the current Technical Guidelines for COVID-19 Vaccination (First Edition) in China recommend that the interval between influenza and COVID-19 vaccinations should be > 14 days. However, existing research has not found clear evidence of immunogenicity and safety concerning inactivated influenza vaccines and combining immunization . Future studies could focus on combining immunization regimens, which is important for the prevention and control of the risk of superimposed epidemics in the future.
This study had several limitations. The HCWs in this study had a higher level of education than HCWs in China in general. Therefore, our findings may not represent the vaccination status of HCWs nationwide. However, the low vaccination rates among these highly educated HCWs also reflected the poor vaccination rates among the general population in China. Second, the vaccination status of HCWs in this study was self-reported rather than based on actual vaccination records, which may be affected by recollection bias. In the future, we will continue to track surveyed HCWs, expand the survey population, and focus on the changes in influenza vaccination order to provide a reference for vaccination and influenza prevention and control.