Mortality from SIM-P (pediatric multisystem inflammatory syndrome) of children in Brazil is eight times that found in the United States.
According to data released in the latest epidemiological bulletin from the Ministry of Health, 1,899 cases of rare syndrome in children were confirmed in the country, with 129 deaths, from the beginning of the pandemic until September 17, 2022.
In the US, data collected by the CDC (Centers for Disease Control and Prevention) point to 9,006 cases of SIM-P registered until October 3, 2022, with 74 deaths.
The case fatality rate in Brazil is thus 6.8% — therefore, 8.2 times that of the US, which is 0.82%. Worldwide, studies have found a SIM-P lethality between 1% and 7%, which would be in agreement with the data indicated in both countries.
Mortality in Brazil is mainly concentrated at the age of 1 to 4 years, with 38 (29.4%) deaths from SIM-P in this age group — for which the federal government has not yet started vaccination.
Brazilian data may also be underreported, as the Ministry of Health has not yet presented a study or tracking of all cases of rare post-Covid syndrome in children, experts recall.
“It is difficult to know the real dimension of SIM-P in the country. We have little data on Covid, and even less on the post-Covid multisystem syndrome”, explains pediatric cardiologist Isabela Back.
Research so far indicates that SIM-P, characterized by an exacerbated reaction of the immune system that ends up attacking the body itself even after discharge from Covid, affects one in 3,000 children.
In addition to SIM-P, cardiac sequelae can also appear in two other conditions, explains the cardiologist: long Covid and during the acute phase of the disease itself. “The data that exist are a smaller number of cases, of children who were hospitalized with Covid, and in those 1 in every thousand children [0,1%] may have cardiovascular disease.”
Back recalls that the country recorded a very high number of cases of severe acute respiratory syndrome (Srag) in minors that can be caused by the coronavirus, but the monitoring of these cases is insufficient to account for the dimension. “Some children may have died from cardiac sequelae without a confirmed Covid diagnosis,” he says.
Children who have worsened Covid, especially those who have been hospitalized, are at greater risk of developing SIM-P or long-term Covid symptoms.
In the latter group, the possibility of cardiac sequelae appearing even months after hospital discharge may continue, and pediatricians reinforce the importance of medical follow-up to assess whether there is damage to the heart.
“Studies carried out here and abroad already show us that there are important cardiac changes that can arise after these conditions [de SIM-P e Covid longa]so the child needs to undergo a cardiovascular evaluation before being released for physical activity,” says Back.
A study carried out by researchers from the Instituto da Criança (ICr) of the Hospital das Clínicas da Faculdade de Medicina da USP pointed out that 48% of the children who were hospitalized at the institute with Covid had cardiological changes, and they were even more frequent in children who developed SIM. -P.
For pediatric cardiologist Gabriela Leal, coordinator of the ICr echocardiogram service and responsible for the study, it is not yet possible to know whether these changes may persist and increase cardiovascular risk in the future.
Covid can cause inflammation and blockages in the small vessels that nourish the heart muscle. Conventional echocardiogram tests are not always able to identify these sequelae, but a differentiated test, such as the one used by ICr researchers, can.
“It is important to emphasize that SIM-P is a rare event and lethality will also depend a lot on the condition of the place where the child receives care, but it is a potentially serious condition. What we want to warn is that even children who are discharged may have some degree of compromise, so it is necessary to continue the follow-up”, he says.
As a result, doctors from the Department of Pediatric Cardiology of the Brazilian Society of Cardiology intend to write a scientific letter with some guidelines for the follow-up of pediatric patients who had severe Covid, SIM-P or long-term Covid symptoms to assess the possible cardiological risks in this case. population.
Scientists still don’t know if there is any genetic predisposition that could be a marker for the risk of cardiac sequelae or if this condition is similar to Kawasaki syndrome – a rare condition of unknown cause that can lead to fevers, rashes on the body and, in severe cases, inflammation of the heart vessels.
“What we observe, however, is that in Brazil children with SIM-P are much younger: while the global average age is 9 years old, here our 5-year-old children have this picture”, says Back.
So far, however, it is known that vaccination, as it is highly effective in preventing severe Covid-19, also helps protect against SIM-P and the risk of post-Covid sequelae.
“It is absolutely necessary that children be vaccinated, and with the complete schedule. There is a lot of misinformation, many parents refuse to vaccinate their children, it is necessary to warn that the vaccine is absolutely safe and with that [a vacinação] we managed to reduce the severe forms of the disease and the risk of cardiovascular sequelae”, says Leal.