Investigating parental perceptions of side effects following vaccination

Background: One of the major factors contributing to parental refusal of vaccinations is the perception that vaccines cause side effects. Although symptoms are commonly reported following vaccinations, their causes are not always straightforward. Although some may be directly attributable to the vaccine itself, others may reflect pre-existing or coincidental symptoms that are misattributed to the vaccine.
Purpose: To investigate psychological factors associated with parental report of side effects following vaccination with the child influenza vaccine, parental intention to re-vaccinate one’s child the following year, and actual rates of re-vaccination.
Methods: A prospective cohort study was run in primary care practices in London in the 2016–17 influenza season (ClinicalTrials.gov number NCT02909855). Two hundred seventy parents from 14 practices completed a questionnaire before their child’s vaccination. Follow-up questionnaires were completed 3 days after vaccination and one month after vaccination. Parental report of side effects and vaccination intention for the subsequent year were measured. Re-vaccination was measured at the end of the 2017-18 influenza season.
Results: Parental report of side effects was strongly associated with pre-vaccination expectation of side effects. Suggestions received from the media, National Health Service (NHS) vaccination leaflet, and health care workers, as well as uncertainty-related beliefs, perceived sensitivity of the child to medicines, pessimism, and anxiety were also associated with reporting side effects. Side effect report was associated with lower vaccination intention for the following influenza season. Eighteen percent of children were not re-vaccinated for influenza in 2017/18. Parental report of severe side-effects three days after vaccination (p = .04) and worry about side-effects one month after vaccination (p = .05) were associated with not re-vaccinating.
Conclusions: Side effect perception following vaccination is influenced by psychological factors, in particular expectations. Perceiving side effects reduces future vaccination intention. Future public health communications should aim to decrease unrealistic expectations of side effects to increase vaccine uptake.

Ethical approval for the study was granted by the NHS Research Ethics Committee (reference: IRAS ID: 192325, REC reference: 16/LO/1003). Following ethical approval, the dataset will be retained until 01/06/2027, then deleted.

背景：导致家长拒绝疫苗接种的主要因素之一，是其认为疫苗会引发不良反应。尽管疫苗接种后常出现各类症状，但其诱因往往并非一目了然。部分症状可直接归因于疫苗本身，而另有一些则可能是原本就存在或偶发的症状被错误归咎于疫苗。

研究目的：探究与儿童流感疫苗接种后家长报告不良反应、家长对次年为孩子再次接种疫苗的意愿，以及实际再次接种率相关的心理因素。

研究方法：本研究为前瞻性队列研究，于2016-2017年流感季在伦敦的基层医疗诊所开展（ClinicalTrials.gov编号：NCT02909855）。来自14家诊所的270名家长在孩子接种疫苗前完成了调查问卷。分别于接种后3天及接种后1个月完成随访问卷，以评估家长报告的不良反应情况及次年的疫苗接种意愿。并于2017-2018年流感季结束时，统计实际再次接种率。

研究结果：家长报告的不良反应情况与接种前的不良反应预期显著相关。此外，从媒体、英国国家医疗服务体系（National Health Service, NHS）疫苗接种手册及医护人员处获得的相关提示、与不确定性相关的认知、孩子对药物的感知敏感性、悲观心态及焦虑情绪，同样与不良反应报告行为相关。不良反应报告与次年流感季的疫苗接种意愿降低显著相关。2017/2018年，有18%的儿童未再次接种流感疫苗。接种后3天家长报告的严重不良反应（p = 0.04）及接种后1个月的不良反应担忧（p = 0.05），与未再次接种行为显著相关。

研究结论：疫苗接种后的不良反应认知受多种心理因素影响，其中尤以预期最为关键。对不良反应的过度认知会降低未来的疫苗接种意愿。未来的公共卫生宣传应致力于降低对不良反应的不合理预期，以提升疫苗接种率。

本研究已获得英国国家医疗服务体系研究伦理委员会（NHS Research Ethics Committee）批准（参考编号：IRAS ID：192325，REC参考编号：16/LO/1003）。获得伦理批准后，本数据集将被保留至2027年6月1日，随后予以删除。