A Brazilian town has seen a 95% drop in COVID-19 deaths after almost all adults were vaccinated as part of an experiment, researchers say.

Serrana, with 45,000 inhabitants, saw cases plunge after a mass vaccination with the Chinese-developed CoronaVac. The team said those who had not been vaccinated were also protected by the reduction in the 
virus’s circulation.

 There were no reports of severe side effects from the vaccine and no Covid-related deaths among those who had been vaccinated 14 days after the second shot was applied, the results showed.

The findings suggest the pandemic can be controlled after 75% of people are fully dosed.

The experiment in Serrana, in the south-eastern São Paulo state, was carried out between February and April by Instituto Butantan, which produces the CoronaVac vaccine developed by China’s Sinovac Biotech.

The city was divided into four areas to help determine the threshold for containing the virus. The team said this was achieved after three areas, or about 75% of the population over the age of 18, had been given both doses.

When 95% of adults were fully vaccinated, they said the results showed that:

• Deaths fell by 95%
• Hospitalisations fell by 86%
• Symptomatic cases fell by 80%

The experiment in Serrana was the first of its kind in the world, its authors said. There were no reports of severe side effects from the vaccine and no Covid-related deaths among those who had been vaccinated 14 days after the second shot was applied, the results showed.

Brazil has the second-highest Covid death toll in the world after the US, and the third-highest number of cases, at more than 
16.5 million.
  Source : BBC