Our researcher Dr.. Rafael Araos explained that the CoronaVac vaccine proved effective at 89% to prevent ICU hospitalizations
- The Ministry of Health delivered the results of the first study "Effectiveness of coronaVac vaccine with inactive SARS-CoV-2 virus in Chile".
- The analysis covered 10 million,500,000 people, of which, four million were inoculated between February 2 and April 1, 2021 with the Sinovac laboratory vaccine.
Dr. Rafael araos, adviser to the Undersecretariat for Public Health, delivered the results of the study "Effectiveness of coronaVac vaccine with inactive SARS-CoV-2 virus in Chile".
The activity involved the Minister of Health, Dr. Enrique Paris, undersecretary of public health, DRA. Paula Daza, undersecretary of Healthcare Networks, Dr. Alberto Dougnac, and the Head of the National Immunization Program, DRA. Cecilia Gonzalez.
The Minister of Health, Dr. Enrique Paris, noted that "to get to this moment, the vaccination process carried out by the government of President Sebastián Piñera, began in May 2020, allowing the first doses of Covid-19 vaccines to arrive last December and initiate a mass inoculation process more than 70 days ago. All this allows us to deliver today the results of this unpublished study, 'Effectiveness of CoronaVac vaccine with inactive SARS-CoV-2 virus in Chile', carried out by the Ministry of Health".
This study, that will be updated monthly, aims to estimate preliminaryly the effectiveness of the CoronaVac vaccine two months after the start of its mass use in Chile. For this, different outcomes were compared in a group of people exposed to the vaccine or not, taking into account age, sex, region of residence, income level, comogability and nationality.
The current national scenario includes 12,726,959 doses administered, of which 7,600,908 correspond to inoculates with a dose and 5,126.051 with two doses, this represents a coverage of 33,7% of a target population to vaccinate 15,200,840. '90s,1% of the population has been inoculated with CoronaVac and 9,9%, with Pfizer-BioNTech.
Dr. Rafael Araos, one of the authors of this research, explained that "the most important idea is that the effect was studied in a cohort, i.e., a group of people who follow in time and who are exposed to the vaccine or not.
Relevant variables were adjusted and events were compared in the two groups". He added that the analysis covered 10 million,500,000 people, four million of whom were inoculated between February 2 and April 1, 2021 with the CoronaVac vaccine.
On the statistical method, Dr. Araos, noted that three elements were considered:
- The instantaneous risk rate (Hazard Risk, Hr) for each group and outcome, using Cox's proportional risk model.
– The predictor-time-dependent version (considers vaccination as a variable predictor over time for each experimental unit)
- effectiveness: 100% x 1 – HR
- Adjusted effectiveness
– Age, sex, region of residence, income run, comogability, nationality
Dr. Araos mentioned three important strengths of the study:
- Data collection and analysis
- Fast, results allow to evaluate short-term effectiveness in "real time"
- Robust database
– Identification and evaluation of clinically relevant outcomes
– Adjustment by covariates
- Sample size
– Estimate of effectiveness in partially and fully immunized individuals
Rafael Araos said that "the effectiveness of CoronaVac at day 14 after the second dose is 67% to prevent Covid-19 symptoms; 85% to prevent hospitalization; 89% to prevent ICU entry, 80% to prevent death due to Covid-19". Delving de further, said that "in simple words, if we take the 67% effectiveness to prevent Covid-19, 100 people who would have had Covid-19, there will only be 33 cases if we are all vaccinated. In both, 80% effectiveness in preventing death due to Covid-19, 100 people who had died from the disease, 20 will do it if we're all vaccinated".
He added that these estimates are conservative and consistent with preliminary results from phase 3 clinical trials (Brazil, Turkey), estimates released by the University of Chile.
Araos added that, to see the biggest benefits of the vaccine, as many people as possible should be immunized, so it is expected that it can soon be added to groups of people not initially included in Phase III clinical trials.
Within the recommendations, the expert explained that it is necessary, "vaccinate with the full schedule and maintain hygiene and personal care measures, alongside the restriction of mobility in accordance with the indications of the health authority".
At last, Dr. Rafael Araos, concluded that "in a scenario of high epidemic activity, the vaccine studied was effective in preventing symptomatic SARS-CoV-2 infection, as well as the most serious forms of the disease. Also, the importance of continuing the vaccination process should be strengthened and that its success depends in large part on achieving as broad coverage as possible. As there are no 100% effective vaccines, it is essential that we all vacun".
The Undersecretary of Public Health, Paula Daza, thanked dr.. Araos and his team for this study that shows good vaccine results. "The conduct of this study was due to a number of reasons. First, Chile has a unique identification system that has allowed all vaccinated people to be monitored since the start of the vaccination process. It is a very important study because it shows the follow-up of millions of people that has allowed us to deliver these results today.
I mean, for Chile this study is very important, but also for the world and scientific society, because it shows us that this vaccine is safe and we must continue the vaccination process".
At last, the Minister of Health, Enrique Paris, thanked the "Ministry of Health team, National Immunization Program (PNI), to the Health Planning Division, Department of Epidemiology, Department of Health Statistics and Information, National Health Fund (FONASA), Institute of Public Health (ISP), To the Primary Care Division (DIVAP), among others.