Immunization is a cornerstone of child survival and remains one of the most cost-effective public-health interventions. Vaccines have contributed substantially to reductions in childhood morbidity and mortality and have enabled control and elimination of several vaccine-preventable diseases. The safety of vaccines is continuously monitored through established surveillance systems because maintaining public confidence is essential for successful immunization programmes.1 The World Health Organization (WHO) defines an adverse event following immunization (AEFI) as any untoward medical occurrence following immunization that does not necessarily have a causal relationship with the use of the vaccine. The event may be a symptom, sign, abnormal laboratory finding or disease.1,2 Therefore, the occurrence of a health event after vaccination does not by itself establish that the vaccine caused the event. Most vaccines are associated with mild and transient reactions such as local pain, swelling, fever or irritability. Serious adverse events are uncommon.3,4 Nevertheless, adverse events occurring temporally after vaccination may generate considerable concern among parents, particularly when they are unexpected or perceived to be severe. WHO recommends systematic AEFI surveillance, investigation and causality assessment to distinguish vaccine-related events from coincidental illnesses, programme-related errors and other causes.2,5 India has an established AEFI surveillance and response system under the Universal Immunization Programme. The National AEFI Surveillance and Response Operational Guidelines emphasize timely notification, investigation, causality assessment and appropriate response to reported events. Effective AEFI surveillance is intended not only to identify genuine vaccine-safety signals but also to sustain public confidence in vaccination.6 Parents are the primary decision-makers for childhood vaccination and their perceptions of vaccine safety can directly influence subsequent vaccine acceptance. A child developing fever, excessive crying, swelling, rash or other symptoms following vaccination may cause parental anxiety and may lead to additional healthcare visits, delayed vaccination or refusal of subsequent doses. Recent qualitative research from South India demonstrated that AEFI experiences were an important contributor to vaccine hesitancy. Parents reported minor adverse events and, in some cases, became hesitant to continue vaccination when children subsequently required medical care. Experiences of AEFI within families also negatively influenced trust in vaccines. The study highlighted the importance of preparing parents for possible AEFI and maintaining transparent communication between healthcare providers and beneficiaries.7 In addition, parents may obtain information regarding vaccine safety from relatives, friends, community members, social media and the internet. Such information may either reassure them or reinforce misconceptions. WHO has emphasized that vaccine-safety events and the way they are communicated can influence public trust in vaccines and health authorities.8 Although quantitative studies can describe the frequency and nature of AEFI, they cannot adequately explain how parents interpret these events, how fear develops, whom parents trust for information and why a perceived AEFI may influence subsequent vaccination decisions. Qualitative inquiry is therefore valuable for understanding these experiences in depth. The present study was undertaken to explore parental perceptions and experiences regarding AEFI among parents attending Government Medical College, Srinagar. The objectives of the study are as below: 1. To explore parental understanding and perceptions regarding adverse events following immunization. 2. To understand parental experiences and emotional responses following perceived AEFI. 3. To explore factors influencing parental decisions regarding subsequent vaccination. 4. To understand parents' experiences with healthcare-worker counselling and AEFI management. 5. To identify perceived barriers to reporting and seeking care for AEFI. 6. To explore parental suggestions for improving AEFI communication and vaccine-safety services.

A qualitative exploratory study was undertaken using purposive sampling, semi-structured individual interviews, iterative coding and thematic analysis. The study was conducted in the Department of Community Medicine, Government Medical College, Srinagar, Jammu and Kashmir, India during 1st Match to 30 April. The study population comprised parents or primary caregivers of children who had experienced a perceived adverse event following routine immunization. A perceived AEFI was defined as any symptom, sign or health event reported by the parent after immunization, irrespective of whether a causal relationship with the vaccine had subsequently been established. This distinction was maintained because temporal association does not necessarily establish causality. Sampling and sample size: Purposive sampling was used. Maximum variation was sought with respect to parental age, sex, residence, educational status, socioeconomic background, child's age and sex, vaccine received, type and perceived severity of AEFI and subsequent vaccination behaviour. Recruitment and analysis were undertaken concurrently, allowing emerging concepts to inform subsequent participant selection. Interviews were continued until thematic saturation, defined as the point at which successive interviews yielded no substantially new concepts relevant to the research questions. A fixed statistical sample size was not calculated because the study aimed to obtain depth and diversity of experiences rather than estimate the prevalence of parental perceptions. Inclusion criteria • were aged ≥18 years; • were the parent or primary caregiver of a child who had experienced a perceived AEFI; • were able to communicate adequately with the interviewer; and • provided written informed consent. • Exclusion criteria • declined participation; • were unable to provide a meaningful account of the child's experience; • had an acute condition preventing completion of the interview; or • had previously participated in the study for the same AEFI episode. Data collection: Data were collected through individual semi-structured, in-depth interviews conducted in a private setting. An interview guide was developed from the study objectives, WHO AEFI guidance and available literature on vaccine safety and parental vaccine hesitancy. Open-ended questions were used to allow participants to describe their experiences in their own words, while probing questions were used to explore emerging issues. Core interview domains a) Understanding of childhood immunization and vaccine safety. b) Parents' understanding of AEFI. c) Description of the child's post-vaccination symptoms. d) Perceived severity and cause of the event. e) Emotional response to the child's symptoms. f) Information received before and after vaccination. g) Healthcare-seeking behaviour. h) Communication and counselling received from healthcare workers. i) Influence of relatives, friends and social media. j) Effect of AEFI on subsequent vaccination decisions. k) Experiences with AEFI reporting and follow-up. l) Suggestions for improving vaccine-safety communication. Interviews were audio-recorded with permission and supplemented by field notes documenting the context of interviews and interviewer reflections. Data analysis: Audio recordings were transcribed verbatim. Transcripts were read repeatedly to achieve familiarity with the data. Initial codes were generated line-by-line and kept close to participants' words. Similar codes were compared and grouped into focused categories. Constant comparison was undertaken across participants with different AEFI experiences and vaccination decisions. Categories were subsequently examined for relationships and organized into broader themes. Coding was iterative, and emerging concepts were incorporated into subsequent interviews. Two researchers independently reviewed a subset of transcripts, discussed discrepancies and reached consensus on the final coding framework. Thematic analysis was used to identify recurring patterns in parental understanding, emotional responses, healthcare experiences, vaccine confidence and subsequent vaccination decisions. Trustworthiness: Credibility was strengthened through purposive maximum-variation sampling, probing during interviews, iterative analysis and prolonged engagement with the research question. Dependability was supported through maintenance of an audit trail documenting interview-guide modifications, coding decisions and theme development. Confirmability was enhanced through reflexive documentation and independent review of a subset of transcripts. Transferability was addressed through detailed description of the study setting and participant characteristics. Ethical considerations: Ethical approval was obtained from the Institutional Ethics Committee of Government Medical College, Srinagar, before commencement of the study. Written informed consent was obtained from all participants. Participation was voluntary, and refusal to participate did not affect healthcare services. Interviews were conducted privately and identifying information was removed from transcripts.

A qualitative exploratory study was undertaken using purposive sampling, semi-structured individual interviews, iterative coding and thematic analysis. The study was conducted in the Department of Community Medicine, Government Medical College, Srinagar, Jammu and Kashmir, India during 1st Match to 30 April. The study population comprised parents or primary caregivers of children who had experienced a perceived adverse event following routine immunization. A perceived AEFI was defined as any symptom, sign or health event reported by the parent after immunization, irrespective of whether a causal relationship with the vaccine had subsequently been established. This distinction was maintained because temporal association does not necessarily establish causality. Sampling and sample size: Purposive sampling was used. Maximum variation was sought with respect to parental age, sex, residence, educational status, socioeconomic background, child's age and sex, vaccine received, type and perceived severity of AEFI and subsequent vaccination behaviour. Recruitment and analysis were undertaken concurrently, allowing emerging concepts to inform subsequent participant selection. Interviews were continued until thematic saturation, defined as the point at which successive interviews yielded no substantially new concepts relevant to the research questions. A fixed statistical sample size was not calculated because the study aimed to obtain depth and diversity of experiences rather than estimate the prevalence of parental perceptions. Inclusion criteria • were aged ≥18 years; • were the parent or primary caregiver of a child who had experienced a perceived AEFI; • were able to communicate adequately with the interviewer; and • provided written informed consent. Exclusion criteria • declined participation; • were unable to provide a meaningful account of the child's experience; • had an acute condition preventing completion of the interview; or • had previously participated in the study for the same AEFI episode. Data collection: Data were collected through individual semi-structured, in-depth interviews conducted in a private setting. An interview guide was developed from the study objectives, WHO AEFI guidance and available literature on vaccine safety and parental vaccine hesitancy. Open-ended questions were used to allow participants to describe their experiences in their own words, while probing questions were used to explore emerging issues. Core interview domains a) Understanding of childhood immunization and vaccine safety. b) Parents' understanding of AEFI. c) Description of the child's post-vaccination symptoms. d) Perceived severity and cause of the event. e) Emotional response to the child's symptoms. f) Information received before and after vaccination. g) Healthcare-seeking behaviour. h) Communication and counselling received from healthcare workers. i) Influence of relatives, friends and social media. j) Effect of AEFI on subsequent vaccination decisions. k) Experiences with AEFI reporting and follow-up. l) Suggestions for improving vaccine-safety communication. Interviews were audio-recorded with permission and supplemented by field notes documenting the context of interviews and interviewer reflections. Data analysis: Audio recordings were transcribed verbatim. Transcripts were read repeatedly to achieve familiarity with the data. Initial codes were generated line-by-line and kept close to participants' words. Similar codes were compared and grouped into focused categories. Constant comparison was undertaken across participants with different AEFI experiences and vaccination decisions. Categories were subsequently examined for relationships and organized into broader themes. Coding was iterative, and emerging concepts were incorporated into subsequent interviews. Two researchers independently reviewed a subset of transcripts, discussed discrepancies and reached consensus on the final coding framework. Thematic analysis was used to identify recurring patterns in parental understanding, emotional responses, healthcare experiences, vaccine confidence and subsequent vaccination decisions. Trustworthiness: Credibility was strengthened through purposive maximum-variation sampling

This qualitative study highlights that parental perceptions of AEFI are shaped by an interaction between the child's symptoms, parental knowledge, emotional responses, previous experiences, social influences and communication with healthcare providers. A major theme was the tendency to interpret a health event occurring after vaccination as being caused by the vaccine. However, WHO clearly distinguishes an AEFI from a vaccine-caused adverse reaction.1,2 Establishing causality requires systematic assessment of available clinical and epidemiological information rather than temporal association alone.2 The perceived severity and duration of symptoms were important determinants of parental anxiety. Mild fever, local pain and swelling may be expected following some vaccines, whereas unexpected or persistent symptoms may generate significant concern. WHO recommends appropriate communication regarding expected vaccine reactions as part of maintaining confidence in vaccination.4,8 The influence of previous family experiences is particularly important. Parents may use personal experiences as evidence when evaluating vaccine safety. The recent qualitative study by Gopalan et al. reported that AEFI experiences within families negatively influenced trust in vaccines and contributed to vaccine hesitancy.7 The present study similarly places family narratives within the broader process through which parents interpret AEFI. Healthcare-worker communication emerged as a major facilitator. Parents wanted information before vaccination rather than only after a reaction had occurred. They particularly wanted to know which symptoms were expected, how long they might last and which symptoms required medical attention. This has important implications for AEFI surveillance. India's 2024 AEFI operational guidelines emphasize prompt reporting, investigation, causality assessment and appropriate response, with the broader objective of sustaining public confidence in vaccines.6 Effective surveillance therefore requires not only technical investigation but also effective communication with parents. Social media and informal information sources may further influence parental interpretation. WHO has emphasized the importance of monitoring public perceptions around vaccine safety because vaccine-related events and their communication can influence trust.8 The potential impact on subsequent vaccination is particularly important. A single negative experience may influence parental decisions about future doses, especially when parents believe the event was caused by the vaccine. Conversely, reassurance from a trusted healthcare provider may help restore confidence.9,10 The findings therefore suggest that AEFI management should be viewed not simply as identification and treatment of an adverse event but as an opportunity for vaccine-safety communication and confidence building. Implications for practice a. Parents should receive standardized information regarding common expected vaccine reactions before immunization. b. Healthcare workers should clearly explain that an event following vaccination does not necessarily mean that the vaccine caused it. c. Parents should be informed about warning signs requiring medical evaluation. d. Suspected AEFI should be appropriately documented and reported according to national guidelines. e. Counselling should acknowledge parental concerns rather than dismiss them. f. Healthcare workers should actively address misinformation originating from relatives, social media and other informal sources. g. Parents experiencing an AEFI should receive appropriate follow-up and reassurance regarding subsequent vaccination. Strengths: The qualitative design allowed exploration of parental experiences and meanings beyond what could be captured using structured questionnaires. Purposive sampling permitted variation in parental experiences and perceptions. Individual interviews provided an opportunity for parents to discuss sensitive concerns regarding vaccine safety and subsequent vaccination decisions. Limitations: The findings of a qualitative study are context-specific and are not intended to estimate the prevalence of particular parental perceptions. Recall and social-desirability bias may influence participants' accounts. Parents may also attribute symptoms to vaccination based on temporal association despite the absence of established causality. If participants are recruited primarily from a tertiary-care facility, parents who experience minor AEFI but do not seek medical attention may be underrepresented. Interviewer characteristics and pre-existing assumptions may also influence data collection and interpretation; reflexivity is therefore important

Parental perceptions of AEFI are influenced by the nature and perceived severity of post-vaccination symptoms, previous family experiences, emotional responses, information from social networks and communication with healthcare providers. Parents may interpret a temporal association between vaccination and illness as evidence of vaccine-related harm, particularly when they have not been adequately counselled regarding expected reactions. Experiences of AEFI may subsequently influence confidence in vaccination and decisions regarding future doses. Improving parental confidence requires more than monitoring and reporting AEFI. Anticipatory counselling, transparent communication, appropriate management and reporting of suspected AEFI, and supportive follow-up should be integrated into routine immunization services. Such measures may help parents distinguish expected vaccine reactions from serious events and reduce unnecessary vaccine hesitancy.

1. World Health Organization. Global manual on surveillance of adverse events following immunization. 2016 update. Geneva: World Health Organization; 2016. 2. World Health Organization. Causality assessment of an adverse event following immunization (AEFI): user manual for the revised WHO classification, 2nd ed, 2019 update. Geneva: World Health Organization; 2021. 3. World Health Organization. Vaccines and immunization: vaccine safety. Geneva: World Health Organization; 2025. 4. World Health Organization. Vaccine safety basics: adverse events following immunization. Geneva: World Health Organization. 5. World Health Organization. Reporting form for adverse events following immunization (AEFI). Geneva: World Health Organization; 2021. 6. Ministry of Health and Family Welfare, Government of India. AEFI surveillance and response: operational guidelines 2024. New Delhi: Ministry of Health and Family Welfare, Government of India; 2024. 7. Gopalan RB, Babu BV, Sarma SK, John RP. Adverse effects following immunisation and vaccine hesitancy: a qualitative study in a South Indian district. Drug Healthc Patient Saf. 2025;17:145-156. doi:10.2147/DHPS.S515064. 8. World Health Organization Regional Office for Europe. How to monitor public opinion: WHO vaccine safety supporting document. Copenhagen: WHO Regional Office for Europe; 2017. 9. World Health Organization. Vaccine safety communication: vaccine safety messages (frequency of AEFIs). Geneva: World Health Organization; 2015. 10. World Health Organization. Mapped reporting form for adverse events following immunization (AEFI). Geneva: World Health Organization; 2022.