Waning effectiveness against COVID-19-related hospitalization, severe complications, and mortality with two to three doses of CoronaVac and BNT162b2: a case-control study

Vincent Ka Chun Yan; Eric Yuk Fai Wan; Xuxiao Ye; Anna Hoi Ying Mok; Francisco Tsz Tsun Lai; Celine Sze Ling Chui; Xue Li; Carlos King Ho Wong; Philip Hei Li; Tiantian Ma; Simon Qin; Chak Sing Lau; Ian Chi Kei Wong; Esther Wai Yin Chan

doi:10.1080/22221751.2023.2209201

Waning effectiveness against COVID-19-related hospitalization, severe complications, and mortality with two to three doses of CoronaVac and BNT162b2: a case-control study

Emerg Microbes Infect. 2023 Dec;12(1):2209201. doi: 10.1080/22221751.2023.2209201.

Authors

Vincent Ka Chun Yan¹, Eric Yuk Fai Wan^{1

2

3}, Xuxiao Ye¹, Anna Hoi Ying Mok³, Francisco Tsz Tsun Lai^{1

4}, Celine Sze Ling Chui^{4

5

6}, Xue Li^{1

4

7}, Carlos King Ho Wong^{1

4

3}, Philip Hei Li⁷, Tiantian Ma^{1

4}, Simon Qin^{1

4}, Chak Sing Lau⁷, Ian Chi Kei Wong^{1

4

8

9

10}, Esther Wai Yin Chan^{1

4

10

11}

Affiliations

¹ Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, Centre for Safe Medication Practice and Research, The University of Hong Kong, Hong Kong, People's Republic of China.
² Laboratory of Data Discovery for Health (D24H), Hong Kong Science and Technology Park, Hong Kong, People's Republic of China.
³ Department of Family Medicine and Primary Care, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.
⁴ Laboratory of Data Discovery for Health (D4H), Hong Kong Science and Technology Park, Hong Kong, People's Republic of China.
⁵ School of Nursing, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.
⁶ School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.
⁷ Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China.
⁸ Research Department of Practice and Policy, School of Pharmacy, University College London, London, UK.
⁹ Aston Pharmacy School, Aston University, Birmingham, UK.
¹⁰ Department of Pharmacy, The University of Hong Kong-Shenzhen Hospital, Shenzhen, People's Republic of China.
¹¹ The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, People's Republic of China.

Abstract

Background: This study aims to evaluate waning effectiveness against severe and fatal COVID-19 with two to three doses of CoronaVac/BNT162b2, where data are limited.

Methods: A case-control study included individuals aged ≥18 years, unvaccinated or received two to three doses of CoronaVac/BNT162b2, using electronic healthcare databases in Hong Kong. Those with first COVID-19-related hospitalization, severe complications, or mortality between 1 January and 15 August 2022 were defined as cases and matched with up-to-10 controls by age, sex, index date, and Charlson Comorbidity Index. Vaccine effectiveness (VE) against COVID-19-related outcomes was estimated at different time intervals from second and third-dose vaccination (0-13 up-to 210-240 days) using conditional logistic regression adjusted for comorbidities and medications.

Results: By 211-240 days after second dose, VE against COVID-19-related hospitalization reduced to 46.6% (40.7-51.8%) for BNT162b2 and 36.2% (28.0-43.4%) for CoronaVac, and VE against COVID-19-related mortality were 73.8% (55.9-84.4%) and 76.6% (60.8-86.0%). After third dose, VE against COVID-19-related hospitalization decreased from 91.2% (89.5-92.6%) for BNT162b2 and 76.7% (73.7-79.4%) for CoronaVac at 0-13 days, to 67.1% (60.4-72.6%) and 51.3% (44.2-57.5%) at 91-120 days. VE against COVID-19-related mortality for BNT162b2 remained high from 0-13 days [98.2% (95.0-99.3%)] to 91-120 days [94.6% (77.7-98.7%)], and for CoronaVac reduced from 0-13 days [96.7% (93.2-98.4%)] to 91-120 days [86.4% (73.3-93.1%)].

Conclusions: Significant risk reduction against COVID-19-related hospitalization and mortality after CoronaVac or BNT162b2 vaccination was observed for >240 and >120 days after second and third doses compared to unvaccinated, despite significant waning over time. Timely administration of booster doses could provide higher levels of protection.

Keywords: BNT162b2; COVID-19; CoronaVac; Omicron; waning vaccine effectiveness.

MeSH terms

Adolescent
Adult
BNT162 Vaccine*
COVID-19* / therapy
Case-Control Studies
Hospitalization
Humans

Substances

sinovac COVID-19 vaccine
BNT162 Vaccine

Grants and funding

This work was funded by a research grant from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region (HMRF Commissioned Research on the Novel Coronavirus Disease; Principal Investigator (WP2): EWC; Ref: COVID1903011). EYFW has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, and the Hong Kong Research Grants Council, outside the submitted work. FTTL has been supported by the RGC Postdoctoral Fellowship under the Hong Kong Research Grants Council and has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, outside the submitted work. CSLC has received grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region, Hong Kong Research Grant Council, Hong Kong Innovation and Technology Commission, Pfizer, IQVIA, and Amgen; and personal fees from PrimeVigilance; outside the submitted work. XL has received research grants from the Food and Health Bureau of the Government of the Hong Kong Special Administrative Region; research and educational grants from Janssen and Pfizer; internal funding from the University of Hong Kong; and consultancy fees from Merck Sharp & Dohme, unrelated to this work. ICKW reports research funding from Amgen, Bristol Myers Squibb, Pfizer, Janssen, Bayer, GSK, Novartis, the Hong Kong Research Grants Council, the Hong Kong Health and Medical Research Fund, the National Institute for Health Research in England, the European Commission, and the National Health and Medical Research Council in Australia, outside the submitted work; and is a non-executive director of Jacobson Medical in Hong Kong and a consultant to IQVIA and World Health Organization. EWC reports grants from Research Grants Council (RGC, Hong Kong), Research Fund Secretariat of the Food and Health Bureau, National Natural Science Fund of China, Wellcome Trust, Bayer, Bristol-Myers Squibb, Pfizer, Janssen, Amgen, Takeda, and Narcotics Division of the Security Bureau of the Hong Kong Special Administrative Region; honorarium from Hospital Authority; outside the submitted work.