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Ciheb Nigeria to Study Adverse Events Following COVID-19 Vaccination

October 26, 2021

A Cohort Event Monitoring (CEM) survey to examine and evaluate the safety of individuals following COVID-19 vaccinations in Nigeria has begun in five states of Bauchi, Edo, Enugu, Kaduna, Lagos, and the Federal Capital Territory, Abuja. This observational surveillance program’s purpose is to monitor safety signal detection following the rollout of COVID-19 vaccines in the country.

The Government of Nigeria, through the National Agency for Food and Drug Administration and Control (NAFDAC), is leading the study in collaboration with Ciheb Nigeria with funding from the U.S. Centers for Disease Control and Prevention.

This survey is designed for an intensive follow-up period of three months following the first and second doses of COVID-19 vaccination, as applicable, and a long-term follow-up for up to three years following the last vaccination.

In the last couple of months, Ciheb Nigeria facilitated trainings for selected follow-up clinicians and data entrants, as well as conducted site assessments and advocacy visits to critical stakeholders. Fieldwork is currently ongoing.

Survey participants are being recruited from six tertiary facilities which serve as COVID-19 vaccination centers across the six geopolitical zones of the country.

With COVID-19 vaccines already introduced in Nigeria, the overall aim of this observational surveillance is to characterize acute events following immunization among persons who receive COVID-19 vaccines.

The CEM survey will estimate the incidence of serious adverse events and adverse events of special interest in all enrolled vaccinees after each vaccine dose or after two doses, classified by COVID-19 vaccine brand. Additionally, the study will evaluate the incidence of reactogenicity events within seven days after each COVID-19 vaccine dose by COVID-19 vaccine brand.

Of note, this active surveillance will address real or perceived safety concerns, particularly in the context of addressing adverse events following vaccinations.


Center for International Health, Education, and Biosecurity
Institute of Human Virology

Andrew Tie
Senior Media and Public Relations Specialist