The world is now dealing with the spread of new variants of the Covid19 as the scientific community races to get vaccines effective against these new mutant variants. It is worthwhile to visit the developments around the vaccines made by pharma-firms based in China, from where the pandemic spread around the world.

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A town in the South American country-Brazil has been transformed into a pandemic oasis of sorts, with the town populace reverting to maskless normal of pre-pandemic times. At an around four hour drive from Sao Paulo, the town of Serrena has seen inoculation of 97.7% of its adult population with a Chinese vaccine. This town was particularly hit hard by the first wave of Covid19. It has inoculated its population (almost entirely at 97.7%) using the shot of CoronaVac developed by China-based Sinovac Biotech.

In another Brazilian city, Manaus, located in Amazon region, preliminary results from a large study of healthcare workers suggest that one dose of CoronaVac is about 50% effective against the symptomatic Covid19. Around 75% of the new cases in the Brazilian city is caused by the Coronavirus variant known as P.1., which is highly transmissible.

The study involved medical data from 67,718 health care workers in the city where the healthcare infrastructure is almost collapsing.

With two doses of the CoronaVac against the standard virus, known in biological parlance as Wild type, the real-world protection is almost at the same levels as shown by the clinical trials. This suggests that the variants’ mutations have not provided the SARS-CoV-2 virus increased ability to evade vaccine-evoked immune responses.

Julio Croda, a physician, and researcher at the Oswaldo Cruz Foundation, who led the study, said, “This is very good news and supports the continued use of this vaccine in Brazil and other countries with the circulation of the same variant.” He added that the protection by the vaccine may even get better after the second dose.

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A 50% effectiveness is far below the 90% real-world protection of the Covid19 vaccines which are made using mRNA. But, it is still considered good enough to be able to contain the disease in Brazil. Effectiveness of 50% in clinical trials qualifies in many parts of the world for emergency uses and can meet the threshold set by the WHO.

The CoronaVac likely offers more protection against severe disease, hospitalization, and death against the milder cases of Covid19. Julio Croda stated that the new study has not collected enough data from severe cases to calculate the effectiveness. The preliminary results of the study, not yet peer-reviewed were posted to a pre-printed server.

Sinovac biotech ltd has been at the centre of controversy for many reasons. For the vaccine developed by the pharma-firm, four divergent efficacy rates were reported ranging from 50% to 91%. Apart from this, Brazil and Turkey had reported wildly divergent data on the CoronaVac within hours, with Brazil reporting 78% and Turkey reporting 91.25% efficacy rates. All these had added to the controversy storm surrounding the Chinese pharms-firm. Recently, it got a shot in its arm when in Indonesia it was reported that the CoronaVac was more protective than the clinical trials had indicated. The study was carried out on 128,000 health workers in Jakarta.

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The CoronaVac developed by Sinovac firm contains inactivated whole copies of the SARS-CoV-2 virus, unlike other vaccines which mostly contain either the spike proteins or the mRNA. Immunopathologist at the Brazil Cancer Institute Bruno Filardi stated that CoronaVac may prove to be better in a general population as the new trial’s data come from healthcare workers who are continuously exposed to the virus.

In addition to China, CoronaVac has been authorized and used in Brazil, Chile, Bolivia, Mexico, Turkey, and Indonesia. Apart from this, the two Chinese manufacturers, Sinovac and Sinopharm are contemplating mixing their jabs and deciding whether a booster shot could help better protect against Covid-19.

It remains to be seen, to what extent the vaccines developed by Chinese Pharma firms like CoronaVac, which are being used by the middle kingdom as a means of vaccine diplomacy in various regions  of the world, succeed in containing and curing Covid19.