Risk of dying from Covid is up to 18 times higher for unvaccinated elderly

The risk of death from Covid was 18 times higher among unvaccinated elderly people, compared to those already immunized, during the wave caused by the ômicron variant in Brazil.

In the adolescent and adult population, unvaccinated people died up to 13 times more in the period.

The analysis was performed by sheet from the crossing of official data from the Ministry of Health with population estimates from the IBGE (Brazilian Institute of Geography and Statistics). The records of deaths and hospitalizations from December to February were considered.

At the peak of the wave, in January, the moving average reached 151 daily deaths per million inhabitants among Brazilians aged 60 and over without any dose received.

Among the elderly protected with at least the first complete regimen —two doses or the single-application immunizer—, the proportional incidence of lethal cases at that time was one tenth of that recorded among non-immunized individuals, with 15 per day.

At the beginning of the increase in the case curve, in December, this difference was 18 times greater. Deaths of unvaccinated elderly people accelerated again (12.6 per million), while deaths among those immunized were falling, at a level below one per million.

Considering the entire period of prevalence and greater circulation of the omicron variant, from December 2021 to February this year, Covid killed on average 9 times more unvaccinated than immunized elderly people.

Among adolescents, young people and adults, the mortality of unvaccinated people was on average 7 times higher in the period.

Overall, considering the population aged 12 and over, vaccinated since last year, daily deaths from Covid reached a peak of 20 per million unvaccinated inhabitants, against 3.6 among Brazilians already protected.

The survey also shows a similar pattern in hospitalizations of patients with severe disease. The incidence was also 9 times higher among the elderly, reaching 16 times higher in the worst moments. In the other age groups, the differences were 6 and 13 times greater, respectively.

These disparities, however, may be greater, since booster doses are not yet included in the official records of admissions from the Ministry of Health.

About 42% of patients hospitalized with serious conditions in the period already had the recommendation to take the additional dose — four months after the first cycle —, but data from Sivep-Gripe (Information System for Epidemiological Surveillance) does not allow us to know how many of them vaccinations were up to date or late.

At the same time, about a third of the qualified population had not yet returned to receive the booster, according to the PNI (National Immunization Program) records.

In addition, not all health units have the same speed and quality of filling out records, especially in municipalities with few resources and less computerized.

In the state of São Paulo, for example, the average in the period was 13 times more deaths among the unvaccinated, considering the population aged 12 years and over. Almost double the national average.

A study carried out by the State Department of Health indicated that this proportion would reach up to 26 times, when taking into account the population aged 5 years and over. The ministry estimates that there would be 716,855 residents without any dose of the vaccine on February 26.

According to data from the Ministry of Health and the IBGE, however, about 7% of the population aged 5 years and over had not received any dose of the vaccine by the end of February, equivalent to 3,112,283 people. When taking this population into account, there would be about 6 unvaccinated deaths for every death of an immunized person.

In the opinion of public health researcher Marcelo Gomes, coordinator of the InfoGripe/Fiocruz system, the survey data reaffirm the success of vaccination and the importance of the booster dose. Especially given the recent increases in cases in Asia and Europe.

“While the virus is circulating, the risk will always be around us. Vaccines do not offer 100% protection, but it is clear that they are doing the job in what they propose. Alone, they will not be able to prevent the emergence of new outbreaks. But this brutal difference in incidence among those who are not immunized must be maintained in possible new waves”, summarizes the specialist.

Gomes also explains that variations in rates over time are to be expected and that care must be taken when analyzing the data, as notification records are subject to delays and noise.

“That is why it is essential that we do statistical analysis to understand how much this difference is expected or if other factors may be involved. The volume of cases itself, the epidemiological increase, new variants and the time between vaccination and a new wave may have a role. There are many variables and many factors.”

The data from the survey of sheet are similar to those released by the CDC (Centers for Disease Control and Prevention) in the United States.

According to the agency, in January, the proportion of hospitalizations caused by Covid in the US was on average 6 times higher among adults and 8 times higher among unvaccinated elderly people over 65 years old.

“Even though the average number of deaths did not keep up with the increase in cases during the omicron explosion in general, we had a new spike in hospitalizations associated with Covid in the 80s and older range in Brazil, which is the most vulnerable population. similar to the peak of March last year. Can you imagine if this population was not vaccinated?”, observes Gomes.

In a technical note released last week, researchers from the Covid-19 Observatory highlighted that the level of vaccine coverage is still irregular in the country.

The study showed, for example, that age groups under 29 still have full-scheme vaccination coverage below 80%. And that no age group had reached this level of vaccinated with the booster dose, even among the elderly.

“Admissions to clinical beds, ICU beds and hospital deaths have increasingly been concentrated exactly among the oldest old. Thus, elderly people who do not maintain a regimen with up-to-date reinforcement are in a particularly dangerous situation, even with the reduction in incidence and mortality in the population as a whole”, warns the note.

The analysis of sheet was based on data from 88,900 severe cases registered throughout Brazil between December and February, of people aged 12 years and over and with information on the patient’s vaccination status.