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After the second dose, CoronaVac is 42% effective for people over the age of 70, says study |  Health

After the second dose, CoronaVac is 42% effective for people over the age of 70, says study | Health

State Government of Sao Paulo / Press release

The study reports that CoronaVac after the second dose is 42% effective in people over the age of 70

The vaccine Corona
It is 42% effective 14 days after application of the second dose in people with an average age of 76 years. The figure was obtained in an international study, with participation USP,
Performed on 15,900 people aged 70 or over in the state of São Paulo. Research also shows that the effectiveness of the vaccine is against: Corona Virus
It falls with age, decreases in size after 80 years, and only taking the first dose provides protection from it Covid-19.
Researchers recommend that vaccination programs include a second dose of Serum,
And that people continue to practice preventive measures, such as wearing masks and avoiding crowds.

The conclusions of the work are in a preliminary version (the earlier version of a scientific article) published on the medRxiv website on May 21. The research evaluated the efficacy of CoronaVac vaccine against symptomatic infections by sars-cov-2
Among residents aged 70 or over in the state of São Paulo, in a context attributed to the most injuries Variant P.1,
That is, it verified whether the vaccine protects against accidental infection in real life, ”explains epidemiologist Ottavio Ranzani, first author of the article. The effectiveness was also evaluated according to age groups and previous injury.

The study covered the period between January 17 and April 29, when a two-dose schedule vaccination of CoronaVac was carried out in São Paulo. “We identified cases of Covid-19 virus confirmed by RT-PCR that were associated with symptoms of the disease with cases of tested subjects who had tested positive for the disease, using data from national surveillance systems and the government vaccination database,” the epidemiologist says. “Cases and negative tests were matched according to age, gender, race, municipality, previous status of the virus, and the date of the RT-PCR test, and from these numbers we estimated the effectiveness of the vaccine, with adjustments for age and comorbidities.

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Of the 26,433 COVID-19 cases and 17,622 people with negative testing, 7,950 couples were selected, resulting in a total assessment of 15,900 individuals with an average age of 76. “We found that the overall efficacy of the vaccine was 42% 14 days after the second dose in a population with an average age of 76 years,” says Ranzani. “The overall effectiveness decreases with age, being higher in people younger than 75 years and decreasing after 80 years. In an exploratory analysis, we found that efficacy is as high as 50% after 28 days of the second dose in populations aged 70 and over.” .

According to the epidemiologist, the loss of efficacy observed in the study was actually to be expected. “The immune system is not optimal with age, and there are other diseases, that is, comorbidities and other aspects, in a process we call immune shrinkage,” he says. “This is true for other vaccines as well.”

The research found no protective effect of the first dose of the vaccine, which, according to the doctor, is an important result of immunization programs. It highlights “It is imperative that programs ensure the second dose of CoronaVac at the time recommended for everyone.” “Programs should plan to improve vaccination for the elderly from the age of 80 and the vulnerable, either by strengthening or changing the type of vaccine, but this still needs to be studied.”

Based on the results of the study, the doctor recommends the necessity to continue preventive measures such as masks, maintain well-ventilated environments and avoid crowding so that we can better control the epidemic. Work on the preprint efficacy of the CoronaVac vaccine in an elderly population during an epidemic associated with the P.1 variant of COVID-19 in Brazil was described: A case study and negative control test, published on the medRxiv website on May 21.

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In Brazil, the research was involved with USP, Fundação Oswaldo Cruz (Fiocruz), University of Brasilia (UnB), Mato Grosso de Sol Federal University (UFMS), Mato Grosso do Sol State University (UEMS), National Institute of Science and Technology in Health Technology Assessment (INCT-IATS) and the Ministry of Health of the State of São Paulo. Researchers from the Pan American Health Organization (PAHO), Barcelona Institute for Global Health (Spain), University of Florida, Yale University and Stanford University (US) were part of the project team.