Knowledge and reporting practices of adverse experiences following immunization

A Survey of Knowledge and Reporting Practices of Primary Healthcare Workers on Adverse Experiences Following Immunization in Alimosho Local Government Area, Lagos.

Running title: Knowledge and reporting practices of adverse experiences following immunization


  1. Riyike A Ogunyemi*. M.B; B.S.
    Onilekere Primary Healthcare Center, Ikeja Local Government, Ikeja, Lagos, Nigeria.
  2. Olumuyiwa O Odusanya FMCPH
    Department of Community Health and Primary Healthcare, Lagos State University
    College of Medicine, Ikeja, Lagos, Nigeria
    *Address for correspondence: Riyike A Ogunyemi
    Onilekere Primary Healthcare Center, Ikeja Local Government, Ikeja, Lagos, Nigeria.


Background: A descriptive cross-sectional survey was conducted among healthcare workers offering immunization services in primary healthcare facilities in Alimosho Local Government Area, Lagos, Nigeria on knowledge and reporting practices of healthcare workers on adverse events following immunization (AEFIs).Materials and Methods: A pre-tested close ended self-administered questionnaire was used to assess knowledge and reporting practices on AEFI. Data was analyzed using statistical package for social sciences (SPSS) version 16. Knowledge of healthcare workers was scored and graded as < 50% poor, 50-74% fair and ≥ 75% good. Reporting practices on AEFI was
classified as good if it was reported within 24 hours of seeing one. A p value of 0.05 was considered statistically significant.

Results: One hundred and sixty-four (164) healthcare workers duly completed and returned
their questionnaires. The mean age was 39.5 ± 2.64 years and mean post-qualification experience was 12.2 ± 2.33 years. Over 80% of the healthcare workers knew that fever, pain, redness and swelling at injection site were clinical signs and symptoms of AEFI, and 93% knew about filling an adverse event form to report an AEFI. Overall, nearly 80% of respondents had fair /good knowledge on AEFI. Fifty-five (33.5%) healthcare workers had encountered an AEFI and 31(56.4%) reported such within 24 hours. There was a significant relationship between being younger healthcare workers and knowledge on AEFIs (p=0.029). No healthcare worker characteristics was significantly associated with good reporting practices on AEFI.

Conclusion: Respondents’ knowledge and reporting practices on AEFI were average.

Key words: Adverse events following immunization, healthcare workers, knowledge,
reporting practices.


Immunization is the process by which a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. [1] Immunization is estimated to avert between 2 and 3 million deaths globally each year, [2] and is stated by the American Center for Disease Control as one of the “ten great public health achievements in the 20th century. [3] Adverse events following immunization (AEFI) is an untoward event temporally associated with immunization that might or might not be caused by the vaccine or the
immunization process. [4] AEFI’s are divided into five categories namely: [4] vaccine product-related reactions
(AEFIs that are caused or precipitated by a vaccine due to one or more of the inherent properties of the vaccine product); and secondly, vaccine quality defect-related reactions (AEFIs that are caused or precipitated by a vaccine that is due to one or more quality defects of the vaccine product including its administration device as provided by the manufacturer).


The remaining categories are: immunization error-related reactions (AEFIs which occur when there is inappropriate vaccine handling, prescribing or administration); immunization anxiety-related reactions (AEFIs arising from anxiety about the immunization); and coincidental events (AEFIs from other factors other than the vaccine product, immunization error, or immunization anxiety).

Under recommended conditions, vaccines should cause no adverse events and completely prevent the intended infections. [5] However, the current technology does not allow for such perfection. In the United States of America, out of every 10,000 cases of vaccination, 1.14 cases of AEFIs were reported and deaths accounted for 1.4% of such AEFIs. [6] In Zhejiang province of China, the overall reporting rate of AEFI was 9.2 per 100,000 doses of vaccination, [7] and in Australia, 14.1 cases of AEFIs were reported per 100,000 doses in 2009, [7] 129.5 per 100,000 vaccine doses in Sri Lanka as at 2012, [8] and 19.3% in a tertiary hospital in Ilorin, Kwara State, Nigeria in 2005. [9] In that institution, the more common AEFIs were local swelling (50.9%), cellulitis (29.7%), injection abscesses (19.3%)
and were reported more with diphtheria, pertussis and tetanus (DPT) vaccine.

[9] A study of occurrence of AEFIs amongst children of mothers in Port-Harcourt, Rivers State, Nigeria reported that up to 57% admitted to having at least one or more AEFIs in their children following administration of the pentavalent vaccine. The main adverse experiences were fever (88%), swelling (34%), and irritability (40%). [10]
The clinical spectrum of AEFI is wide with fever being the most frequently reported ‘serious’ and ‘non-serious’ AEFI for all age groups. [11] Fever was the most commonly reported general adverse event among Nigerian infants who received the 10- valent pneumococcal non-typeable Haemophilus influenza protein D conjugate vaccine. [12] In Sri
Lanka, the AEFI reporting rate for the pentavalent vaccine was 296.8 per 100,000 doses administered in 2012. High fever, allergic reactions, nodules, severe local reactions, seizures and injection site abscesses were the leading AEFIs reported in one study. [8] At the extreme of the clinical spectrum of AEFI is anaphylaxis, which is an acute hypersensitivity reaction with multi-organ system involvement that may rapidly progress to a life threatening reaction.

Though rare, with an incidence rate of 0.65 cases per million doses of vaccine, [13] anaphylaxis is a well-known AEFI that may occur following immunization without a prior warning. Even though AEFIs are well known, not much is known about how healthcare workers recognize or report them. Reporting AEFIs is important in recognizing the occurence of rare events for new vaccines which may not be known during clinical trials or to monitor the rates of such events for well-established vaccines. Poor knowledge of AEFI among healthcare workers will result in many cases of AEFI going unreported and unaddressed, which may undermine confidence in national immunization programs, as well as reduce immunization uptake and have a negative public health. impact. A study examining Canadian family physicians awareness of vaccine associated adverse events, showed that less than half of the
study respondents were aware of a monitoring system for AEFI, one third knew of the reporting criteria, and only one in four had received vaccine adverse events education during medical training.

[14] A study in the United States of America (USA) among physicians, pharmacists and nurses that examined reporting systems, the frequency of reporting of vaccine adverse events, beliefs and awareness of AEFI found that 71% had never reported AEFI, and 17% indicated they were not aware of how to report. [15] A study from the United Kingdom (UK) on AEFI reporting of Meningococcal serogroup C conjugate vaccine found that nurses reported AEFIs more frequently than general practitioners and hospital doctors. [16] Amongst mothers in Awe Local Government Area of Kwara State, Nigeria, concerns about safety of vaccines was a major reason for non-completion of immunization.

[17] Although in Enugu, up to 80% of mothers would not allow such experiences deter them from immunizing their children. [18] It would then seem that adverse experiences may be a limiting factor to full uptake of vaccines. Immunization services are received by the majority of children at primary health care facilities, knowing that AEFIs may occur is important and therefore should be known and reported by health care workers administering vaccines at
these facilities. Thus the objective of this study was to determine the knowledge and reporting practices of healthcare workers on AEFI in primary healthcare facilities in Alimosho Local Government Area (LGA).

Materials and Methods

Alimosho LGA is a densely populated suburb of Lagos State with a population of 1,288,714 as at the 2006 national census. It is one of the fifty-seven (57) Local Government/Local Council Development Areas in Lagos. Alimosho is a semi-rural area and one of the largest LGA in Lagos. It is divided into six administrative zones: Alimosho Local Government, Agbado-Okeodo Local Council Development Area (LCDA), Ayobo-Ipaja LCDA, Egbe-Idimu LCDA, Ikotun-Igando LCDA and Mosan-Okunola LCDA. The people of Alimosho enjoy a rich supply of health care services from both private and government providers.

The government owned health facilities include the Alimosho General Hospital, Igando, and the twenty-nine Primary Healthcare Centers which are located within the six administrative zones of the LGA. There were 214 health workers offering clinical services at the primary health care centres in the LGA.

Sample size determination and selection of participants

The minimum sample size for the study (N=178) was determined using Fisher’s formula, with standard normal deviation at 95% confidence interval (1.96), prevalence rate of 0.71 [15] (proportion of healthcare workers who were aware of the reporting system for AEFIs) andprecision of ± 7% (0.07). However, only healthcare workers directly involved with vaccination and management of AEFI were eligible. Non-consenting staff involved in vaccination were excluded. All eligible (n=176) healthcare workers were included in the study.

Study instrument, data collection and analysis

A self-administered, close ended questionnaire was developed for this study from a review of the literature.

The instrument inquired on demographic details, knowledge of healthcare workers on: signs and symptoms of AEFI, reportable AEFIs and methods of reporting AEFI. It also took to cognizance trainings on AEFI that healthcare workers might have received. Furthermore, the healthcare workers were asked about encounters with AEFIs and their reporting practices. Perceived barriers to reporting AEFI were also sought for.

The questionnaire was pre-tested among 53 (30% of the intended sample size) healthcare workers at Orile Agege Local Government Area. The pre-test was carried out to fine tune the study instrument and to remove ambiguities in the phraseology. Face validity of the instrument was done by the study supervisor through repeated checking of the instrument with relevant literature to ensure that it could achieve the objectives of the study. The reliability of the instrument was determined using the Cronbach’s coefficient alpha which was 0.7.

The questionnaires were distributed to the eligible healthcare workers after immunization clinic sessions at each health facility over a two-week period in February 2015, and were collected as soon as the questionnaires were filled. The duly completed questionnaires were analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 16.

Descriptive statistics was computed to generate frequencies, means and standard deviations. The knowledge of the healthcare workers was determined using a total of thirty-four questions; each correct answer was scored one mark giving a maximum score of 34. Scores of 75% and greater (26-34 marks) were graded as good knowledge, scores between 50% and 74% (17-25) were graded as fair knowledge and scores below 50% (0-16) were graded as
poor knowledge. Reporting practices on AEFI was classified as good if it was reported within 24 hours of seeing one. Statistical significance was asset at p-value ≤ 0.05. Chi-square test

was used to measure the association between dependent variables (knowledge and reporting practices on AEFI) and independent variables (demographic data of healthcare workers and training on AEFI).

No portion of this work or publication should be used in digital or printed formats without the express permission of the main researcher Dr Riyike Ogunyemi

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