Adverse events following immunization attributable to measles vaccine are rare

Evaluation of the adverse events following immunizations surveillance system in Harare City, Zimbabwe, 2016: a descriptive cross sectional study

Introduction

Vaccines safety are monitored by looking for Adverse Events Following Immunizations (AEFIs). A review of the 2014 Harare City consolidated monthly return form (T5) revealed that 28 AEFIs were seen in 2014. However, only 21 were reported through the system. We therefore evaluated the Harare City AEFI surveillance system to assess its usefulness.

Methods

A descriptive cross sectional study was conducted. Twenty one of 41 clinics were randomly selected and 51 health workers were randomly recruited. Interviewer administered questionnaires were used to collect data. Epi info 7 was used to generate frequencies, means and proportions.

Results

Out of 51 respondents, 50 (98%) knew the purpose of AEFI system, 48 (94%) knew at least two presenting symptoms of AEFIs and 39 (77%) knew the correct date of form submission to the next level. Receiving no feedback 24 (47.1%), fear of victimisation 16 (31.4%) and work overload 11 (21.6%) were the major reasons for under reporting. Eighty six percent perceived the system to be simple and 43 (84%) were willing to continue participating. Fifty three percent (27) reported taking public health actions (such as awareness campaigns & making follow ups) basing on AEFI data collected. All 46 reviewed forms were completely filled and submitted in time. All 21 clinics had written AEFI guidelines and case definitions. Only 14 of 21 clinics had adequately stocked emergency drugs. The total cost for a single notification was estimated at US$22.30.

Conclusion

The system was useful, simple, acceptable, timely, stable, representative but costly. The good performance of the system reported in this evaluation could be attributed to high health worker knowledge. Following this evaluation, replenishment of out of stock drugs and follow up of missing 2014 AEFI feedback from MCAZ were done. In addition, making the system electronic is recommended.