Accelerating vaccination can prevent 430 deaths of children aged 5 to 11 by April, study says

Vaccination against Covid in children aged 5 to 11 years in Brazil is at a slow pace, with about 250,000 doses applied per day. If this vaccination were accelerated to the ideal – according to experts, one million doses a day –, by April, 5,400 hospitalizations and 430 deaths from Covid in this age group would be avoided.

This projection is part of an unprecedented study carried out by the modeling group of the transmission dynamics of the coronavirus in Brazil, which includes researchers from UFRGS (Federal University of Rio Grande do Sul), UFG (Federal University of Goiás), USP (University of of São Paulo), Unesp (Universidade Estadual Paulista), UFABC (Federal University of ABC) and the Covid-19 BR Observatory.

In the general population, faster vaccination would also be of benefit. According to the projection, it would have the effect of preventing about 14,000 hospitalizations and more than 3,000 deaths from the disease in all age groups in the same period.

In the study, the researchers did mathematical modeling to estimate how many deaths and hospitalizations would be preventable under three distinct scenarios: a no-child vaccination (hypothetical) scenario, the current slow-paced scenario, and the ideal or accelerated dose delivery scenario.

The ideal scenario considers other childhood vaccination campaigns of the National Immunization Program (PNI) which has already reached the application of 1 million doses per day.

The direct and indirect impacts of childhood immunization were considered within a period of three months after the start of vaccination, that is, from January to April.

At the current rate, the vaccination campaign in children has the potential to avoid 5,718 hospitalizations and 1,092 deaths, with a confidence interval of 95%.

When separated by age groups, the current pace of childhood immunization should prevent 2,367 hospitalizations and 182 Covid deaths in children aged 5 to 11 years.

In Brazil, from the beginning of the pandemic until February 7, 6,877 hospitalizations and 308 deaths from Covid in children were recorded.

In the study, the model analyzes the “chance of passage” from one category to the others, according to the classification: susceptible (people who have not yet received the vaccine), exposed and transmissible (people in the infectious phase of the disease), asymptomatic, mild symptomatic , hospitalized, recovered and deaths.

The chance of a person from one category moving to another is calculated considering each of the above scenarios and parameters such as type of vaccine (Pfizer, AstraZeneca and Coronavac) and vaccination schedule (one dose, two doses or three doses).

The pace considered ideal is not a distant reality, from a first world country, says Roberto Kraenkel, physicist and researcher at the Covid-19 BR Observatory.

“If we had vaccination at an acceptable rate, the number of deaths from Covid that could be avoided by April is of the same order of magnitude as the total number of children who died in this age group since 2020, which indicates that there should indeed be an acceleration”, he says. .

In addition to direct protection for children, accelerating the pace of childhood vaccination brings benefits from the point of view of controlling the epidemiological situation in all age groups.

“Society is not separate, people of different ages have contact with each other and in particular with children between 5 and 11 years old, although lethality is very low, it is not zero. But for adults over 60 years of age, the possibility of hospitalization and death is much higher, and these people have direct contact with the children, they are parents, grandparents, teachers”, explains Kraenkel.

For Kraenkel, the model manages to demonstrate exactly this blockage in the transmission. “The model is able to show how many people of other age groups are being indirectly protected by childhood vaccination because there is a cut in the virus transmission chain”, she says. “In short, it’s ‘vaccinate your kids to protect grandpa’.”

Cristiana Toscano, coordinator of the group and representative of the Brazilian Society of Immunizations of Goiás, reinforces that, although at the beginning of the pandemic in a society still completely susceptible and with the ancestral form of Sars-CoV-2, children in fact did not have a role so important in the transmission of the virus.

“When we made progress in protecting the population, what happened is what we are experiencing now: a portion of adolescents still partially vulnerable, because they did not take both doses, and younger children with a large contingent still susceptible [apenas 23% das crianças tomaram a primeira dose no país]. So the transmission in this age group becomes much higher,” he says.

Toscano recalls that, although proportionally the number of hospitalizations and deaths in the younger age groups are not so high compared to the older ones, in absolute numbers, when you have a large number of people getting sick with the ômicron variant, this ends up being a aggravating even for children and adolescents.

“This understanding is important to make the decision and guide parents in relation to vaccinating their children”, he says.

For her, the pandemic situation brought with it a new type of vaccine hesitancy, different from what was observed in other moments of the PNI. “This is mainly due to the context of large circulation of disinformation, conflicting data and incorrect information, to make it very clear”, she says.

The problem could be circumvented if there was a national coordination of the childhood vaccination campaign, which has not been done so far, evaluates the researcher.

“In the beginning, one of the bottlenecks was the lack of doses, but today there are municipalities with stopped doses. [da Saúde] will say that there are no difficulties, that the doses are left over, but we know that among the factors that are currently influencing the low vaccination coverage are insecurity and ignorance. [da importância de vacinar as crianças] due to the lack of an organized strategy, based on evidence, with national dissemination”, he says.