Delta variant, immune response and vaccines, what do we know today about children against the coronavirus? – Telam

The impact of the Delta variant of the coronavirus in the infant population, the immune response of girls, boys and adolescents, and current vaccines for this group are some of the topics developed by doctor and researcher Lourdes Arruvito, who in dialogue with Tlam has thrown in some keys on how to care for this age group in this time of pandemic.

Arruvito is a researcher at the Institute for Biomedical Research on Retroviruses and AIDS (Inbirs), which depends on the Faculty of Medicine of UBA and Conicet, and one of the authors of the works known this week in which he has It was possible to identify characteristics of a type of white blood cell that would explain why some children have severe symptoms and others very mild or almost non-existent of Covid-19.

In this interview, I engage with Tlam on the issues that most concern mothers and fathers today about the coronavirus around the world.

Tlam: How does the Delta variant affect girls, boys, and teens?

Lourdes Arruvito: A higher number of cases have been observed in children who live in countries where this variant is predominant. In recent weeks, for example, American Academy of Pediatrics has confirmed significant increase in Covid-19 cases in people under 18; which extends to both children and adolescents, but also adults.

What we’re still trying to figure out is whether people get sicker with the Delta variant or not. These are surprisingly difficult things to disentangle. When there is a large increase in the number of people infected, it results in a proportionately higher number of people hospitalized and more people dying. But that doesn’t necessarily mean the virus itself is deadlier.

There is no convincing evidence so far that any of the variants have a particular propensity to infect or cause more disease in children.

T: What do we know so far about how SARS-CoV-2 affects boys, girls, and adolescents, regardless of the variant?
LA: Most SARS-CoV-2 infections in children are mild or don’t cause any obvious symptoms. The reasons behind this are unclear. One of the hypotheses is that the pediatric population has a lower amount of angiotensin-converting enzyme 2 (ACE 2) in the airway epithelium, and ACE2 is a receptor that allows entry of coronavirus in the cell, as if it were out of the lock. However, a small group of children can experience more severe symptoms in two ways. On the one hand, a small percentage of boys and girls (with or without previous conditions) can develop a serious inflammatory disease called multisystem inflammatory syndrome (MIS-C) within two to eight weeks of infection with SARS-CoV. -2.

This can happen even in children with mild asymptomatic symptoms. The clinical picture is characterized by cardiac, pulmonary, renal, cerebral, hematological and cutaneous-mucous membrane damage, and in most cases requires hospitalization, admission to intensive care or even ventilatory and hemodynamic assistance.

There is so far no convincing evidence that any of the variants have a particular propensity to infect or cause more disease in children.“

On the other hand, some children may have severe manifestations such as severe pneumonia or neurological symptoms in the acute stage of the disease. In this case, in general, it was found that they were children with previous illnesses and requiring hospitalization and several times also hospitalization in the intensive care unit.

According to official data from Argentina’s Ministry of Health, as of August 9, 2021, 542,362 cases and 294 deaths have been confirmed in children under the age of 20. Likewise, 208 cases of MIS-C have been confirmed and 1 died after this syndrome.

The mortality of children under 5 due to Covid-19 alone has equaled the number of deaths from respiratory diseases in recent years. 25% of the deceased children were less than one year old and 60% had previous illnesses.

T: What do we know to date about the immune response of the pediatric population?
LA: In the work that we carried out between researchers from Inbirs and the medical staff of eight port and peri-urban hospitals, in addition to the conclusions on the characteristics of different neutrophils in seriously ill children and those who are not, we also found good levels of antibodies with the ability to neutralize the virus in almost all of the groups of boys and girls we studied.

Antibody levels remained high for at least 2-3 months.

However, we do know that children who have suffered severe infection did not develop an IgG antibody response to the Spike protein at detectable levels, unlike that seen in asymptomatic children or children with mild and moderate symptoms.

This observation raises a possible causal link between a faulty antibody response and the development of severe Covid-19. Likewise, it appears that the response mediated by T cells may be weaker than in adults. This type of immune response to the virus makes this population of children very vulnerable.

What’s more, work in Israel has shown that neutralizing antibodies in children who contract the virus start to decline after as little as four months. This may indicate that children have a weaker long-term immune response.

These types of results are very relevant in deciding vaccination policies in the pediatric population.

T: Considering that vaccination in most countries of the world is not yet available for those under 18, how can they protect themselves?

LA: In our country, the vaccination of girls, boys and adolescents between 12 and 17 years old with co-morbidities, that is, diseases that make them more vulnerable to the virus, has started.

The most important thing we can do to protect the girls and boys who are not yet eligible for vaccination is to ensure that as many people as possible around and interacting with them get vaccinated. Anyone over 18 should receive the vaccine, both to protect themselves and to protect those who are not yet eligible (such as children and adolescents). We know that vaccines are very effective in preventing serious illness, hospitalizations and death in those who receive them, and we also know that they will significantly reduce the risk of passing the infection on to another person. Anyone who has the vaccine should be vaccinated. This is the only way to end the pandemic.