CoronaVac

CoronaVac, also known as the Sinovac COVID-19 vaccine,^[4] was a whole inactivated virus COVID-19 vaccine developed by the Chinese company Sinovac Biotech.^[5][6] It was phase III clinically trialled in Brazil,^[7] Chile,^[8] Indonesia,^[9] the Philippines,^[10] and Turkey^[11] and relies on traditional technology similar to other inactivated-virus COVID-19 vaccines, such as the Sinopharm BIBP vaccine, another Chinese vaccine, and Covaxin, an Indian vaccine.^[12] CoronaVac does not need to be frozen, and both the final product and the raw material for formulating CoronaVac can be transported refrigerated at 2–8 °C (36–46 °F), the temperatures at which flu vaccines are kept.^[13]

A real-world study of tens of millions of Chileans who received CoronaVac found it to be 66% effective against symptomatic COVID-19, 88% effective against hospitalization, 90% effective against ICU admissions, and 86% effective against deaths.^[14] In Brazil, after 75% of the population in Serrana, São Paulo, received CoronaVac, preliminary results show deaths fell by 95%, hospitalizations by 86%, and symptomatic cases by 80%.^[15][16] In Indonesia, real-world data from 128,290 healthcare workers showed 94% protection against symptomatic infection by the vaccine, beating results in clinical trials.^[17]

Phase III results from Turkey, published in The Lancet, showed an efficacy of 84% based on 10,218 participants in the trials.^[18][19] Phase III results from Brazil previously showed 50.7% efficacy in preventing symptomatic infections and 83.7% effectiveness in preventing mild cases needing treatment. Efficacy against symptomatic infections increased to 62.3% with an interval of at least 21 days between the doses.^[20]

CoronaVac is being used in vaccination campaigns in various countries in Asia,^[21][22][23] South America,^[24][25][26] Central America,^[27][28][29] and Eastern Europe.^[30][31][32] By April 2021, Sinovac had a production capacity of 2 billion doses per year.^[33] It was manufactured at several facilities in China,^[33] with overseas manufacture planned for Brazil in September 2021^[34] and eventually Egypt^[35] and Hungary.^[36]

On 1 June 2021, the World Health Organization (WHO) validated the vaccine for emergency use.^[37][38] Sinovac has signed purchase agreements for 380 million doses from COVAX.^[39] As of July 2021, CoronaVac was the most widely used COVID-19 vaccine in the world, with 943 million doses delivered.^[40]

As of 14 October 2021, CoronaVac is the COVID-19 vaccine with the most doses administered worldwide.^[41]

It was reported in December 2021 that a study jointly conducted by the LKS Faculty of Medicine, The University of Hong Kong (HKUMed), and the Faculty of Medicine, The Chinese University of Hong Kong (CU Medicine), showed that a third dose of the Comirnaty vaccine given to those who received two doses of either Comirnaty or CoronaVac provided protective levels of measured antibodies against the Omicron variant of SARS-CoV-2. Three doses of CoronaVac, however, did not provide adequate levels of protective antibodies by the same measure,^[42] in direct contradiction to claims made by the vaccine manufacturer.^[43][44]

In October 2022, a Hong Kong study found that two doses of CoronaVac provided protection of only 64% to 75% for older adults. However, an extra booster or a third dose of CoronaVac was able to raise the level of protection against COVID-19 to about 98%.^[45]

In January 2024, Sinovac confirmed that it had discontinued production of CoronaVac.^[46]