The mass vaccination strategy against covid-19, implemented in a period of much misinformation throughout the health crisis in Brazil, prevented the death of 54,000 to 63,000 people aged 60 or over from January to August 2021. period, immunization prevented 158,000 to 178,000 hospitalizations of elderly people in Brazilian hospitals.
The estimates, considered conservative, were presented by researchers from the Covid-19 BR Observatory in article published in the journal “The Lancet Regional Health Americas”🇧🇷 The work was supported by Fapesp (São Paulo State Research Support Foundation) and had the participation of groups from Unesp (São Paulo State University), Oswaldo Cruz Foundation, Unicamp (State University of Campinas), UFABC (Federal University of ABC) and USP (University of São Paulo).
To arrive at these numbers, the researchers concentrated on the first months in which the vaccines began to be applied in the country and on the age groups of the elderly, the first to complete the vaccination schedule according to the immunization program schedule. By tracing the curve of deaths and hospitalizations due to covid in the Brazilian population, superimposing it on the similar curve in the groups of elderly people who were being immunized by the SUS (Sistema Único de Saúde) in 2021, the positive correlation between vaccination and death prevention was evident and severe cases: the more vaccine coverage increased in the elderly, the smaller the impact of SARS-CoV-2 infection in these groups aged 60 years or older.
With the analysis model built, assuming that immunization is directly related to the drop in severe cases and deaths and that exposure to the virus was the same for all age groups over the period analyzed, different scenarios were estimated to compare them with a supposed scenario of total absence of immunization. Hence, it was possible to observe a reduction of approximately 35% in hospital admissions of the elderly from January to August 2021.
Taking as a basis that each hospitalized person had, during the pandemic, an average cost of US$ 12,000 in Brazil, avoiding 158,000 to 178,000 hospitalizations represented an estimated saving of US$ 1.9 billion to US$ 2.1 billion over health system, impact compared by the researchers in the article to the US$ 2.2 billion invested in immunizations by the country in the analyzed period, until August 2021.
“Our model assumes that the behavior of the epidemic, in different age groups, is the same. Not in the sense that they have the same number of cases, but that they have the same up and down behavior, more or less at the same time. If we take an age group that is not receiving the vaccine at that moment and compare it with an age group that is receiving the vaccine, there is a difference in this behavior. The number of severe cases in the elderly began to decline, while the number of hospitalizations among younger people continued to rise. This behavior is due to vaccination in the older population. This is the explanatory variable for the difference between the two age groups”researcher Leonardo Souto Ferreira, first author of the article and researcher at IFT-Unesp (Institute of Theoretical Physics) told Unesp’s press office. “The fact that vaccines have made a difference is indisputable.”
MORE LIVES COULD HAVE BEEN SAVED
The study goes beyond quantifying the number of lives saved by vaccines in Brazil. The researchers’ analysis built another 2 scenarios to scale how many lives could have been saved and how many hospitalizations could have been avoided if mass vaccination against covid started with a faster rate of application of doses, as verified 4 weeks later and 8 weeks after the initial immunization date, January 18, 2021. These scenarios are described as moderate and high acceleration of immunization, respectively.
Although it started in January, immunization in Brazil gradually gained scale:
- 250,000 doses per day were reached from February to March;
- 500,000 daily doses was reached from April to May; and
- 1 million doses per day were consumed in June 2021.
If the rate of application of doses of the immunization campaign had been that verified 8 weeks after its beginning, for example, the number of deaths of elderly people could have been 40% to 50% lower in relation to that observed at the peak of the concern variant range of SARS-CoV-2, according to the study. Estimates indicate that another 47,000 elderly lives could have been saved and approximately an additional 104,000 hospitalizations could have been avoided in a scenario of further acceleration of immunizations.
The spread of the gamma variant was marked by a dramatic health crisis in Manaus, Amazonas, in January last year and determined more extreme attitudes on the part of some public agents, such as the lockdown enacted in February in the city of Araraquara (SP).
“Although we could not prevent the emergence of the gamma variant, given that it appeared in November and vaccines were made available in January, a rapid vaccination could considerably reduce the peak of hospitalizations and deaths, especially among the elderly and especially in states where this strain took a while to arrive”says researcher Flávia Maria Darcie Marquitti, from the Gleb Wataghin Institute of Physics and the Institute of Biology, both at Unicamp.
The study highlights that, in mid-2021, the immunization of the Brazilian population fulfilled a “decisive role” to prevent a further severe wave of hospitalizations and deaths as another worrying variant of SARS-CoV-2, delta, began to spread across the country and become prevalent. At that point, vaccination was already at a very fast pace, similar to that of previous campaigns, such as the application of doses against the H1N1 virus in 2010, when SUS vaccinated 88 million people in 3 months. “When the delta arrived, it found it more difficult to circulate”, says Marcelo Gomes, co-author of the study and researcher at Fiocruz.
The researchers claim that the 1st generation vaccines against covid allow our body to “learn it” about a certain virus without the person suffering the impact of the infection brought by it, avoiding the risk of aggravation and death. “This needs to be very clear to our population. Vaccines have a tremendous social impact, both direct and indirect. The smaller the number of hospitalizations, the better we can allocate resources to care for those who still end up getting worse or who suffer from other diseases”points out Gomes.
Although the study focuses on the population over 60 years old, for the researchers, it dialogues with the issue of childhood vaccination. Approved in the 2nd half of December 2021, immunization of the public aged 5 to 11 years was started in the 2nd half of January 2022, coinciding with the peak of the omicron variant of SARS-CoV-2.
Questions created around childhood vaccination contributed to what researchers call “vaccine hesitancy”, that is, doubts on the part of the population regarding the safety and efficacy of immunizers. Since the beginning of the pandemic, in March 2020, covid has already caused the death of around 689 thousand people in the country.
In addition to Fapesp, the authors also received support from Capes (Coordination for the Improvement of Higher Education Personnel), CNPq (National Council for Scientific and Technological Development), Faperj (Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro) and Inova Fiocruz.
The article “Estimating the impact of implementation and timing of the COVID-19 vaccination program in Brazil: a counterfactual analysis” can be read here🇧🇷
*With information from FAPESP Agency
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