Omicron wave led to 3 in 4 children and teens getting Covid in the US, says CDC

The wave of the omicron in the United States has led 3 out of 4 of children and adolescents up to 17 years of age in the country to have specific antibodies against the coronavirus in the body, which may indicate a previous infection with the virus.

This value, which represents the so-called seroprevalence rate, jumped from 44.2% in children aged 0 to 11 years, between September and December 2021, to 75.2%, between December 2021 and February 2022 —a analysis is done every four weeks. In the case of young people aged between 12 and 17, the rate increased from 45.6% to 74.2%.

The data were released in a report by the American CDC (Centers for Disease Control and Prevention) on the 26th. The analysis of blood samples to look for specific antibodies against the nucleocapsid (core protein) of Sars-CoV-2 in the period made it possible to evaluate how this change was directly related to the emergence of the omicron variant of the coronavirus in the country.

According to the study, the general seroprevalence rose between 0.9 and 1.9 percentage points in the months from September to December 2021. Between December and February, the reported growth was from 33.5% to 57.7% ( 24.2 percentage points).

Although the increase was also noticed in adults over 18 years of age, the growth in the younger age group represented an increase of about 30 percentage points in the omicron period. In older individuals, the prevalence increased from 36.5% to 63.7% in adults aged 18 to 49 years; from 28.8% to 49.8%, in those aged 50 to 64 years; and from 19.1% to 33.2% in individuals aged 65 years and over.

Also according to the agency, this increase in younger age groups may be directly related to the fact that children and adolescents have lower rates of vaccine coverage against Covid and, thus, are more susceptible to new infections.

In January, data from the CDC itself pointed to a 520% ​​increase in new pediatric Covid admissions compared to the pre-omicron period, and hospitals across the country also saw an increase in respiratory symptoms in children, likely linked to the omicron.

The two-dose vaccine coverage rates in April in the country were 28%, among children aged 5 to 11 years; 59% for adolescents aged 12 to 17; 69%, in adults aged 18 to 49 years; 80%, in individuals aged 50 to 64 years; and 90% for those aged 65 and over.

The report requested data on Covid cases in children and adolescents aged 0 to 17 years in Brazil from the Ministry of Health from January to April 2022, but did not receive a response until the publication of this report. From the beginning of the pandemic until February 7, 2022, 6,877 hospitalizations and 308 deaths from Covid in children were recorded.

According to data from the consortium of press vehicles, until this Wednesday (4), 27.08% of children aged 5 to 11 years in Brazil received both doses of the Covid vaccine.

For immunologist Cristina Bonorino, a professor at the Federal University of Health Sciences in Porto Alegre, the data found in the US should raise an alert for Brazil, which does not have large-scale data on antibodies against Covid in the population, especially in the pediatric population.

“This is really very worrying because we don’t know in the long term what the virus is capable of doing in the body. From what we know of evidence so far, the immune response is very variable after infection. That’s why vaccination is essential.” reflects.

The researcher highlights the importance of vaccines protecting not only against acute diseases, but also against consequences. “There are several vaccines and infectious diseases that were previously known very little about the long-term consequences, and today we already know. [vírus do papiloma humano], for example, is one of them. There is a clear relationship between having the virus infection and the incidence of cervical or head and neck cancer in adulthood, so vaccinating children is essential to prevent this. Covid is the same thing, we don’t know the consequences that a coronavirus infection can cause in children, even a few months after infection “, he explains.

According to data from the epidemiological bulletin of the Ministry of Health for the week of April 10 to 16, 2022, since the beginning of the pandemic, 2,927 suspected cases of SIM-P (pediatric multisystem inflammatory syndrome) have been reported in children and adolescents aged 0 to 16. 19 years, of which 1,702 (about 58%) were confirmed, and 113 deaths.