Clinical outcomes and risk factors for SARS-CoV-2 breakthrough cases following vaccination with BNT162b2, CoronaVac, or ChAdOx1-S: A retrospective cohort study in Malaysia

Hessa Tamim; Rosnani Hashim; Nurdiana Jamil; Li Yin Chong; Zainol Johari

doi:10.1016/j.heliyon.2024.e29574

Clinical outcomes and risk factors for SARS-CoV-2 breakthrough cases following vaccination with BNT162b2, CoronaVac, or ChAdOx1-S: A retrospective cohort study in Malaysia

Heliyon. 2024 Apr 20;10(8):e29574. doi: 10.1016/j.heliyon.2024.e29574. eCollection 2024 Apr 30.

Authors

Hessa Tamim¹, Rosnani Hashim¹, Nurdiana Jamil¹, Li Yin Chong², Zainol Johari¹

Affiliations

¹ Faculty of Pharmacy, University of Cyberjaya, Persiaran Bestari, Cyber 11, 63000, Cyberjaya, Selangor, Malaysia.
² Sultan Idris Shah Serdang Hospital, Jalan Puchong, 43000, Kajang, Selangor, Malaysia.

Abstract

Background: The SARS-CoV-2 pandemic drove global vaccination. However, breakthrough infections raised concerns about vaccine performance, leading the World Health Organization (WHO) to recommend investigations thereof. This study aimed to evaluate the clinical outcomes (time to breakthrough infection, intensive care unit [ICU] admission, and in-hospital mortality) of hospitalised patients with SARS-CoV-2 breakthrough infection. This was the primary outcome and the risk factors associated with its severity were the secondary outcomes.

Methods: This retrospective cohort study at a multispecialty tertiary hospital in Selangor, Malaysia included 200 fully adult vaccinated patients, with confirmed SARS-CoV-2 infection, admitted from September 2021 to February 2022. Participants were selected by simple random sampling. Infection severity was categorised as CAT 2-3 (mild-moderate) and 4-5 (severe-critical).

Results: The time to breakthrough infection was significantly longer for BNT162B2 recipients (128.47 ± 46.21 days) compared to CoronaVac (94.09 ± 48.71 days; P = 0.001) and ChAdOx1-S recipients (90.80 ± 37.59 days; P = 0.019). No significant associations were found between SARS-CoV-2-related ICU admission, mortality, and the vaccines. Multivariable analysis identified vaccine type, variant of concern, ethnicity, and hypertension as significant predictors of severity. BNT162b2 and ChAdOx1-S recipients had significantly (81 % and 74 %, respectively) lower odds of CAT 4-5 infection compared to CoronaVac recipients. Indian patients had a significantly (83 %) lower chance of CAT 4-5 infection compared to Malay patients. Patients with breakthrough infections during the Omicron period had a significantly (58 %) lower risk of CAT 4-5 compared to those in the Delta period. The CAT 4-5 risk was significantly (nearly threefold) higher in hypertensive patients.

Conclusion: The results support the Malaysian Ministry of Health's recommended booster three months after primary vaccination and the WHO's recommended heterologous booster following CoronaVac. Certain ethnic groups, hypertensive patients, and viral variants may require attention in future pandemics.

Keywords: BNT162B2; Breakthrough infection; COVID-19; COVID-19 vaccines; ChAdOx1-S; CoronaVac; SARS-CoV-2.