O Globo Agency | @journalovale
All the seven Covid-19 vaccines that are already the subject of contracts and negotiations in Brazil are already moving towards testing children. Six of them have clinical trials planned or started outside Brazil, and one of them, Johnson & Johnson, has requested authorization for research in the country.
The process of researching and registering products for use by children is required by law in the country, but it should take less than that of adults. The adoption in public child vaccination programs, however, is still not certain, given the delay in Brazil in the campaign to vaccinate adults and the elderly, more susceptible to Covid-19.
– The idea of childhood vaccination in this case is based on two main reasons – explains Renato Kfouri, president of the Scientific Department of Immunizations of the Brazilian Society of Pediatrics (SBP) – One of them is to offer protection against Covid-19 for children who have chronic problems , such as diabetes and heart disease, and are more vulnerable to the virus. The other is in a situation where we would already have all adults (immunized) and we would like to increase the number of vaccinees to try to reduce the rate of transmission of the virus.
From what some published results from the first stages of clinical tests on children indicate, both objectives are feasible.
This week, the first efficacy result for a vaccine in minors was announced, that of the companies Pfizer / BioNTech, but only for teenagers.
The companies had already included a group of 16 to 17 years old in their first tests, then expanded the sample with some between 12 and 15 years old. In the younger group, the vaccine showed 100% effectiveness after a phase 3 study of 2,260 adolescents. Last week, a test arm was started on children aged 6 months to 11 years, still in phase 1, to test safety.
“The companies plan to submit this data to the FDA and EMA (American and European regulatory agencies) to request an amendment to the authorization for emergency use of the vaccine in adolescents aged 12 to 15 years as soon as possible,” Pfizer said in a statement. There is still no report on requests for authorization or tests in Brazil.
The first child to be vaccinated for Covid-19 in Brazil must receive the immunizer from the Janssen division of Johnson & Johnson) in the context of a clinical trial. According to the company, the order for the test is already in the hands of Conep (National Council for Ethics in Research) and Anvisa (National Health Surveillance Agency).
“Janssen’s Covid-19 vaccine will be tested initially on a small number of adolescents,” the company said in a statement. “The volunteer recruitment process will be conducted directly by the selected research centers, after approval.”
In the opinion of Greyce Lousana, president of the Brazilian Society of Professionals in Clinical Research (SBPPC), although now Anvisa does not require testing in Brazil for the approval of vaccines, immunizers who have volunteer children in the country can speed up their process evaluation.
– This is good, because by the time the vaccine is registered for this population, the doctors who participated in the tests are already familiar with the vaccine – explains the researcher. – It is also relevant for the local regulatory authority, because it keeps monitoring all the time.
Of the Covid-19 vaccines already used in Brazil, none have yet announced their intention to run tests here. Chinese Sinovac, creator of CoronaVac, has already published results of phase 1 tests, indicating that it is safe in children. The preliminary analysis of immunogenicity (ability to instigate the production of antibodies) was positive.
The Butantan Institute, a partner of Sinovac, however, has not yet informed whether it is negotiating to open a clinical trial arm of CoronaVac in children in Brazil.
The University of Oxford, a partner of AstraZeneca, started in February to recruit a group of 300 children and adolescents for a phase 2 test to assess the immunogenicity of the vaccine in the group between 6 and 17 years old. Unifesp (Federal University of São Paulo), which tested the vaccine in Brazil, has not yet said that it is negotiating to enter phase 3.
The creators of the vaccine say they have the ambition that it will be used in large-scale campaigns among children.
“The Covid-19 pandemic had a profound negative impact on education, social, emotional development and the well-being of children,” said Rinn Song, a pediatrician involved in the Oxford University trial. “It is important, then, to collect data on the safety and immune response of the coronavirus vaccine in these age groups, so that they can come to benefit from the potential inclusion in vaccination programs.”
Pharmacovigilance problems that AstraZeneca has faced in Europe, however, can delay plans for children. Although some European countries have suspended use of the product due to the reporting of adverse effects, Anvisa has not shown a similar concern.
Other vaccines for which the Brazilian government has announced a purchase contract – the Russian Sputnik V, and the Indian Covaxin – have also announced the intention of a clinical trial in children. As these two vaccines have not yet gained registration for use in adults at Anvisa, however, it is unlikely that they will be among the first ones released for child use in the country.
The United Kingdom, which is in the early stages of evaluating various vaccines for child use, estimates that in October it may start vaccinating children. Brazil has not yet announced a forecast.
Despite the setbacks in testing some immunizers, Kfouri, of the Brazilian Society of Pediatrics, says he is optimistic about the prospect of use in children,
– It is not a surprise to see these vaccines showing safety and efficacy in children as good or even better than in adults – he says. – It would be unexpected to see any of these vaccines causing a serious problem in children.
Lousana recalls, however, that children’s clinical trials are not just a formality.
– You can’t do the tests on children without the same rigor that we use for adults – he says.
Get the latest news delivered to your inbox
Follow us on social media networks