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Spotlight Session - Vaccines

Session: Spotlight Poster Session B

(BSPOT51) Signal Monitoring for Adverse Events Following Immunization with COVID-19 Vaccines During the SARS-CoV-2 Pandemic: An Evaluation of the South African Surveillance System

Tuesday, August 27, 2024
8:00 AM – 6:00 PM CEST
Location: Foyer 3

    Presenting Author(s)

  • CS

    Chenoa Sankar, MPH, MSc.

    Epidemiologist at the National Institute for Communicable Disease
    Center for Vaccines and Immunology, National Institute for Communicable Disease, South Africa

    • Co-Author(s)

  • KM

    Kerrigan McCarthy

    Clinical Pathologist at the National Institute for Communicable Disease
    Centre for Vaccines and Immunology, National Institute for Communicable Disease, South Africa

  • JM

    Johanna Meyer

    Professor in the School of Pharmacy, Sefako Makgatho University
    South African Vaccination and Immunisation Centre, Sefako Makgatho Health Sciences University, South Africa

  • HG

    Hannah Gunter

    Senior lecturer at the University of Cape Town
    Division of Clinical Pharmacology, Department of Medicine, Faculty of Health Sciences, University of Cape Town and Groote Schuur Hospital, Cape Town, South Africa, South Africa

  • SE

    Stephen Evans

    London School of Hygiene and Tropical Medicine, United Kingdom

  • VS

    Victoria Sekiti

    Pharmacovigilance Officer
    South African Health Products Regulatory Authority (SAHPRA), South Africa

  • MS

    Marione Schonfeldt

    National Cold Chain Manager
    National Department of Health, South Africa

  • DM

    Dini Mawela

    Professor
    Sefako Makgatho Health Sciences University, South Africa

  • HD

    Halima Dawood

    Head of Clinical Unit: Infectious Diseases
    Greys Hospital, KwaZulu-Natal, South Africa

  • SD

    Sipho Dlamini

    Associate Professor
    Division of Infectious Disease and HIV Medicine, University of Cape Town, South Africa

  • JP

    Jonny Peter

    Head of the Division
    Allergology and Clinical Immunology at Groote Schuur Hospital, University of Cape Town and the Allergy and Immunology unit, UCT Lung Institute, South Africa

  • LM

    Lawrence Mubaiwa

    Head of Division
    Paediatric Neurology and Child Development, University of KwaZulu-Natal, South Africa

  • CG

    Clive Gray

    Professor
    Immunology in Molecular Biology and Human Genetics, University of Cape Town, South Africa

Background: South Africa, a country with over 66 million people, administered two authorized SARS-CoV-2 vaccines (BNT162b2 and Ad26.COV2.S) from 17/02/2021. Surveillance for adverse events following immunization (AEFI) was co-ordinated by the National Department of Health (NDoH). Effective post-licensure surveillance is essential to monitor vaccine safety.

Objectives: We investigated whether the AEFI surveillance system could detect signals of disproportionate reporting for COVID-19 vaccines and whether these signals aligned with globally identified AEFI and adverse events of special interest (AESI).

Methods: This pharmacovigilance study undertook disproportionality analysis of the NDoH AEFI database from the time of COVID-19 vaccine rollout to 31/12/2022. We complemented this with non-COVID-19 vaccine AEFI reports from 01/01/1992 - 17/02/2021 to address potential masking of signals due to high reporting of COVID-19 vaccines-related AEFIs. Statistical analyses were conducted in R Studio (2023.06.1), using the Bayesian Confidence Propagation Neural Network method for detection of disproportionality between observed and expected reporting of vaccine-adverse event combinations. A signal was defined as the lower limit of the 95% credibility interval of the Information Component (IC025) >0.

Results: Up until 31/12/2022, 37,537,009 million SARS-CoV-2 vaccine doses were administered, and 3846 COVID-19 AEFIs reported (10.2/100,000 vaccine doses), with 18.1 and 7.9 AEFIs/100,000 doses reported for Ad26.COV2.S and BNT162b2 respectively. Comparison of reporting rates with other countries suggests underreporting in our setting. Seven signals of disproportionate reporting (IC025 >0) were identified for Ad26.COV2.S (headache, myalgia, pyrexia, dizziness, injection site pain, nausea, chills) and three for BNT162b2 (dyspnea, chest pain, rash). An additional three AEFI signals for Ad26.COV2.S (pain, injection site swelling, fatigue) and two for BNT162b2 (dizziness, fatigue) emerged in the augmented dataset, indicative of masking. All Ad26.COV2.S signals, and two BNT162b2 signals (dizziness, fatigue), are documented in the vaccine product information (PI). Among 9 AESI evaluated, only myocarditis/pericarditis presented as a signal of disproportionate reporting following BNT162b2 vaccination.

Conclusions: This study is one of the first from a LMIC using a spontaneous reporting system for signal detection. We identified AEFI signals that correspond with COVID-19 vaccine PI, despite evidence of underreporting, thus demonstrating the capability of our surveillance system to detect signals. We identified the need to strengthen surveillance by investigating reasons for underreporting.