Comparative Safety and Effectiveness of Heterologous CoronaVac-ChAdOx1 versus Homologous CoronaVac Vaccination in a Real-World Setting: A Retrospective Cohort Study

Ayakarn Ruenkham; Suriyon Uitrakul; Peninnah Oberdorfer; Siriporn Okonogi; Wasan Katip

doi:10.3390/vaccines11091458

Comparative Safety and Effectiveness of Heterologous CoronaVac-ChAdOx1 versus Homologous CoronaVac Vaccination in a Real-World Setting: A Retrospective Cohort Study

Vaccines (Basel). 2023 Sep 5;11(9):1458. doi: 10.3390/vaccines11091458.

Authors

Ayakarn Ruenkham¹, Suriyon Uitrakul², Peninnah Oberdorfer^{3

4}, Siriporn Okonogi^{5

6}, Wasan Katip^{3

6

7}

Affiliations

¹ Department of Pharmacy, Srisangwan Hospital, Mae Hong Son 58000, Thailand.
² Department of Pharmaceutical Care, School of Pharmacy, Walailak University, Nakhon Si Thammarat 80160, Thailand.
³ Epidemiology Research Group of Infectious Disease (ERGID), Chiang Mai University, Chiang Mai 50200, Thailand.
⁴ Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
⁵ Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand.
⁶ Center of Excellence in Pharmaceutical Nanotechnology, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand.
⁷ Department of Pharmaceutical Care, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand.

Abstract

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has outpaced vaccine availability and delivery from vaccine manufacturers, and thus, a scarcity of vaccines happened to many countries around the world. In Thailand, the mixing of different types of vaccines was approved and clinically implemented partially due to concerns about the availability and efficacy of one vaccine. Objective: This study aimed to investigate the effectiveness and safety of heterologous CoronaVac-ChAdOx1 nCoV-19 vaccines compared with the usual regimen of homologous CoronaVac-CoronaVac. A retrospective cohort study was conducted by dividing patients into the CoronaVac-CoronaVac group and the CoronaVac-ChAdOx1 group. Results: A total of 875 patients received vaccinations at Srisangwan Hospital between April to October 2021 and were included for analysis. The patients in both homologous and heterologous groups had low rates of COVID-19 infection. In addition, the hospitalization rates in the 40 days after the second vaccination were low in both regimens. Minimal adverse events (AE) were reported in both groups, including local AE (e.g., discomfort at the injection site, rash, soreness, swelling, and redness) and systemic AE (e.g., fever, headache, weariness, nausea, vomiting, diarrhoea, and myalgia). Moreover, several factors were associated with lower adverse events following immunization (AEFIs), including age ≥ 50 years, male, and body weight ≥ 50 kg. In contrast, thyroid disease, diabetes mellitus, allergic rhinitis, and psychiatric disorders were independent risk factors associated with an increase in AEFIs. Conclusions: The heterologous CoronaVac-ChAdOx1 and homologous CoronaVac-CoronaVac regimens were promising vaccination strategies for the prevention of SARS-CoV-2 infection. However, the heterologous CoronaVac-ChAdOx1 potentially caused fewer AEFIs compared with the homologous CoronaVac-CoronaVac regimen.

Keywords: ChAdOx1; CoronaVac; heterologous vaccine regimen; homologous vaccine regimen; real-world setting.

Grants and funding

This research received no external funding.