How did a Small Town in Brazil Control COVID-19?

Woman in Brazil receives COVID-19 vaccine
Source: Reuters

A small town in Brazil saw a 95% drop in deaths from COVID-19, all thanks to a mass vaccination experiment.

Brazil is one of the hardest-hit country in the COVID-19 pandemic. With more than 460,000 total deaths, it has the second highest death toll in the world. The blame of which mostly lies on the shoulders of Brazilian President Jair Bolsonaro and his government. His opposition to lockdown measures and skepticism around vaccines has had a significant impact on the country’s healthcare. The slow pace of immunization and the lack of vaccines, thanks to the government policies, has further pushed the country into a pit of despair.

Amid all this chaos, one small town in the state of Sao Paulo has managed to completely control the spread of COVID-19. While its neighbours deal with rising infections, the town of Serrana is now returning to normal. All thanks to an experiment labelled ‘Project S’.

The town of almost 46,000 was part of a study that aimed to assess the real-world effectiveness of the Chinese vaccine, CoronaVac. As a first step, researchers divided the town’s population into four geographic areas. As per protocol, all residents 18 years and above received two shots of the vaccine 4 weeks apart. Pregnant women and those suffering from chronic diseases were not included in the project.

At the start of the project, 1 in 20 Serrana residents had COVID-19. However, once 75% of the population received their second dose, the number of cases began to plummet. Results showed an 86% drop in hospitalizations, 80% decrease in symptomatic cases, and a 95% drop in COVID-related deaths.

The most important result was understanding that we can control the pandemic even without vaccinating the entire population

Ricardo Palacios, study coordinator

A Return to Normal

Ricardo Palacios, an epidemiologist at the Butantan Institute that conducted the project, has described Serrana as an healthy oasis.

Although Serrana never closed its borders with neighbouring towns, the vaccination program still managed to drastically control the spread of COVID-19. Moreover, the results point to the effectiveness of CoronaVac in controlling the virus, despite its low efficacy in clinical trials.

CoronaVac uses an inactivated version of the SARS-CoV-2 virus to evoke an immune response. Unlike other vaccines, it has demonstrated a vaccine effectiveness of a little over 50%. A number that is significantly lower than its mRNA counterparts. However, the results from Serrana paint a different picture. Moreover, scientists find the results encouraging in the face of the Brazilian variant called P1, which is the most prevalent strain in the country.

Although the results of the study are promising, researchers caution that it might be too early to trust the results. It is still unclear as to how long immunity lasts after the second dose and whether booster shots are required. Therefore, the research team plans to follow the town’s residents for one year to track their immunity.

On Tuesday, the World Health Organization (WHO) granted CoronaVac an emergency use authorization. Making it the second Chinese vaccine to receive approval. Its easy storage and low cost will help low-income countries control the spread of infection.

The world desperately needs multiple COVID-19 vaccines to address the huge access inequity across the globe. We urge manufacturers to participate in the COVAX Facility, share their know-how and data and contribute to bringing the pandemic under control.

Dr Mariângela Simão, WHO Assistant-Director General for Access to Health Products


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