6 questions about vaccination in children, authorized by Anvisa in Brazil

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The vaccination of children aged 5 to 11 years against Covid-19 with the immunizing agent from Pfizer was authorized in Brazil, this Thursday (16), by Anvisa, the National Health Surveillance Agency.

Now, the application of the vaccine (also called Comirnaty) is allowed, but, for it to occur in practice, it depends on the doses (which will have a different bottle and composition from those of adolescents and adults) being acquired and distributed by the Ministry’s National Immunization Program of Health — which, for the time being, has said only that “it will analyze the decision of Avisa”.

“The authorization came after a careful technical analysis of data and clinical studies conducted by the laboratory. According to the Agency’s technical team, the information evaluated indicates that the vaccine is safe and effective for children”, informs Anvisa, which is also evaluating a request from the Butantan Institute for the Coronavac vaccine to be or not applicable to children aged 3 to 17 years. The agency has 30 days to complete its review.

The following are six questions and answers about what is known about vaccination in children so far, including possible risks and benefits and how it has been happening in other countries:

Will the vaccine for children be different from that for adults?

Yes. Anvisa informed that Pfizer’s vaccine for children has a different dosage and composition than what is already being used for those over 12 years old.

First, the dosage: in children, the immunizing agent will have to be applied in two doses of 0.2 ml (equivalent to 10 micrograms, one third of that of adults), with at least 21 days between doses.

It is not yet known whether this will be the term adopted in practice, since intervals between doses have depended, until now, on the availability of the vaccine.

In addition, says Anvisa, “the lid of the vaccine bottle (for children) will come in orange, to facilitate identification by the vaccination teams and also by the fathers, mothers and caregivers who will take the children to be vaccinated. those over 12 years old, the vaccine, which will be applied in doses of 0.3 mL, will have a purple cap”.

There will also be differences in the concentration of mRNA (the component of the vaccine that stimulates the immune system’s response), in the number of doses per vaccine vial and in the storage time of the immunizing agents.

Why vaccinate children against Covid-19, which tends to be lighter in young ones?

Although severe cases and deaths from Covid-19 in children are proportionately few compared to adults, the sheer numbers paint a worrisome picture.

In a video presented during Anvisa’s announcement on Thursday, Dr. Rosana Richtmann, a consultant to the Brazilian Society of Infectious Diseases, highlighted that around 2,500 Brazilian children and adolescents have died from Covid-19 since the beginning of the pandemic.

Physician Renato Kfouri, representative of the Brazilian Society of Pediatrics, drew attention to the fact that, currently, Covid-19 kills more than all other infectious diseases included in the childhood vaccination calendar.

“In addition, we need to take into account the complications of coronavirus infection in this age group, such as the risk of multisystem inflammatory syndrome, the long Covid, hospitalization and the entire burden related to this disease,” said the pediatrician.

“It is important to highlight the warning from the WHO (World Health Organization), which points out that the public between 5 and 14 years is the most affected by the new wave of Covid-19 in Europe and, despite the lower risk compared to other age groups , no other vaccine-preventable disease caused as many deaths in children and adolescents in Brazil in 2021 as Covid-19,” said, in a statement, Carlos Lula, president of the National Council of Health Secretaries (Conass).

“The pandemic is not over yet and the complete vaccination of the entire Brazilian population is urgent.”

As the US Centers for Disease Control (CDC) points out, “when a child takes Covid-19, they can be sick for days, miss school days and other learning and play opportunities.”

In addition, the agency says, “unvaccinated children who get Covid-19 may be at risk for problems linked to prolonged post-covid, hospitalization, Multisystem Inflammatory Syndrome (P-SIM, when different parts of the body are affected by severe inflammation) or death”.

What is known about the effectiveness of the vaccine in children?

According to the CDC in the USA, a country where the Pfizer vaccine is already applied to children aged 5 to 11 years, the effectiveness of the immunizing agent in preventing Covid-19 infection in this public is over 90%.

Here, it is noteworthy that omicron, a new variant of the coronavirus, appears to be more effective in partially circumventing the immune system’s protection, but studies of its effects so far focus on the adult audience.

The EMA, the European drug regulatory agency, also recommended in November that Pfizer’s vaccine be used for children ages 5-11.

In the study analyzed by the European agency, the effectiveness of the vaccine in preventing symptomatic Covid-19 was 67.7% to 98.3%.

According to the EMA, “the main study of children aged 5 to 11 years showed that the immune response to Comirnaty (name of the immunizer from Pfizer) with a lower dose (10 micrograms) in this group was comparable to that seen with the higher dose (30 micrograms) in the public aged 16 to 25”, if the level of antibodies produced against the coronavirus is taken into account.

The European study concluded that “the benefits of Comirnaty in children ages 5 to 11 outweigh the risks, particularly in those under conditions that increase the risks of Covid-19”, adding that risks and efficacy will continue to be monitored across the continent.

What is the risk of side effects and what is known about them?

In studies evaluated by the European regulatory agency, the most common side effects of vaccines in children were the same as in older people: pain, redness and swelling at the injection site, tiredness, headache, muscle aches and chills.

“These effects are usually mild or moderate and pass a few days after vaccination,” said the EMA.

The US CDC also pointed out that, according to studies analyzed in the US, with thousands of children, “no safety concerns were identified after vaccination, and side effects were not lasting. Some children will not experience side effects, and the most serious effects are rare”.

Among these rare effects, myocarditis — a type of inflammation in the heart — is one that has become a topic of discussion among parents. In this regard, two studies were published in recent days, showing that the risk of myocarditis after vaccination is very low, being even much lower than that of myocarditis associated with Covid-19.

Let’s go to them:

This Thursday (16), the FDA, the US drug regulatory agency, released a study by a doctor who is part of its vaccination task force. In it, the highest incidence of myocarditis after vaccination with Pfizer was observed among adolescents aged 16 to 17 years, with an incidence of only 0.007%.

According to the CDC, hears only eight reports of cases of myocarditis among children aged 5 to 11 years vaccinated, in a universe of 7 million doses applied, reported the Reuters agency on Thursday (16). The cases were all mild. The government agency stated that it is not possible to establish a causal relationship between vaccination and myocarditis so far.

Also on Thursday, Anvisa highlighted that the advantages of vaccination in children outweigh the risks of myocarditis.

Meanwhile, a second study looking at myocarditis and other cardiac ailments was done in the UK (and made public on December 14th), in a universe of people who had received the Oxford/AstraZeneca, Pfizer and Moderna vaccines.

And the main finding was that the risk of developing heart problems after vaccination was at most 10 in 1 million.

“Although there is some increased risk of rare cardiac complications associated with vaccines, it is much less than the risk associated with Covid-19 infection,” said the study’s lead author, Julia Hippisley-Cox, professor of clinical epidemiology at the University of Oxford.

“For example, we estimate between 1 and 10 extra myocarditis events in 1 million people vaccinated with the first or second dose, but 40 extra cases per million in people with Covid-19.”

“However, it is important that we know and identify the risks of these rare vaccine problems, to ensure that physicians know what to look for, help with early diagnoses, inform decisions and manage resources,” he added.

Has Pfizer’s vaccine been tested in children?

The general manager of Medicines and Biological Products at Anvisa, Gustavo Mendes, explained that the release of the Pfizer vaccine for children aged 5 to 11 years was based on two main studies carried out by the pharmaceutical company.

The first research aimed to verify the safety and tolerance of the product in three different dosages: 10, 20 and 30 micrograms.

The results showed that the dose of 10 micrograms is the most suitable for this age group and induces a good immune response, with a robust production of neutralizing antibodies against Covid.

In the second study, 2,268 children were divided into two groups. Two-thirds of them took two doses of the vaccine with an interval of 21 days between applications. The rest received placebo, a substance with no effect on the body.

“In the comparison between the two groups, the safety profile is very positive and there were no important differences between those who received the vaccine or the placebo. There were no reports of serious adverse events, of major concern”, says Mendes.

“Regarding the effectiveness, we can easily see in the study’s graphs that the group that took placebo had a higher incidence of cases of Covid-19 compared to those who received the vaccine”, summarizes the representative of Anvisa.

The agency also said that it made its decision to release the immunizer with the help of a group of experts in pediatrics and immunology.

“The look of external experts was an additional criterion adopted by Anvisa so that the use of the vaccine by children was approved within the strictest criteria, considering for this the knowledge of medical professionals who work on a daily basis with children and immunization”, he says the organ.

Which countries already vaccinate children of that age against Covid-19?

A survey carried out in early December by the Reuters agency pointed out that the number of countries to include children in the vaccination against Covid-19 has grown, as concerns grow about the advancement of the omicron variant.

In the US and Canada, the recommendation to vaccinate the group from 5 to 11 years old has been in effect since November.

In European Union countries, the distribution of Pfizer vaccines to be applied to children aged 5 to 11 years began on December 13th.

In some countries, such as Spain, application started to take place a few days later. In others, such as Germany, the expectation is to vaccinate children from the beginning of 2022.

In the UK, an official decision on whether or not to vaccinate children under 12 is expected before Christmas.

In the Middle East, Pfizer’s vaccine has been approved for children in Israel, Oman, Saudi Arabia, Bahrain and the United Arab Emirates.

In Asia, China has approved Sinopharm and Sinovac (CoronaVac equivalent) vaccines for children aged 3 years and older, and Zhejiang province is aiming to complete vaccinations in ages 3 to 11 by the end of this month.

Singapore and Japan plan to start immunizing the 5- to 11-year-old group in January and February respectively. The same should happen in Australia.

In Latin America, Cuba already administers vaccines for children from 2 years of age; Argentina, for children over 3 years old; Chile and El Salvador began vaccinating the 6- to 11-year-old group in September.

In Costa Rica, vaccination has become mandatory for children aged 5 years and older.

It is noteworthy, however, that so far the primary recommendation of the WHO is to improve the (unequal) distribution of vaccines in the world, prioritizing still vulnerable adult audiences

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