COVID-19: impact on the pediatric population.

As we all know, SARS-CoV-2 virus was the cause of the pandemic in 2020 and it is a respiratory virus that can also affect children. The clinical spectrum of COVID-19 is broad, in most cases in pediatrics it presents as an asymptomatic disease or with mild symptoms.

Although children of any age are easily infected with the virus and can transmit it efficiently in their family, social or school environment, the probability of suffering from symptomatic COVID-19, especially in its severe form, is markedly lower than in adults. The likelihood of suffering symptomatic COVID-19, especially in its severe form, is markedly lower than in adults. The reason for this is not fully understood, but appears to have to do with differences in the functioning and maturity of the immune system in infants compared to adults.

However, as we will see below, COVID-19 can also present in severe forms in children and be associated with the development of chronic disorders such as diabetes.

Although initial data regarding cases, complications and deaths led to consider that COVID-19 had a low impact on the pediatric population, current data show that the infection causes direct and indirect undesirable effects on children clinically, socially, educationally, emotionally and in the family.

By December 2022, at least 15 million children worldwide were reported to be infected with SARS-CoV-2, most with a mild clinical course and with a low, but not negligible, mortality of 0.1%, especially in those with underlying disease.

Despite this, in the United States in 2022 COVID-19 was the leading cause of death from respiratory disease in children. The percentage of hospitalizations and mortality rate remains significantly lower in pediatrics compared to adults, but tends to be higher than those caused by other immunopreventable infections typical of childhood such as influenza, pertussis, hepatitis A, rotavirus, varicella, among others.
In Latin America, children under 18 years of age account for less than 5% of all hospitalizations due to COVID-19. Mortality has been low in most countries of the region, affecting mainly children under 1 year of age.

As previously mentioned, SARS-CoV-2 causes a mild clinical picture in children, with fever, headache or irritability, cough, sore throat, loss of smell and altered taste.

In addition to mild acute infection, similar to other viral illnesses, COVID-19 has been associated with the development of a number of conditions following infection such as multisystem inflammatory syndrome in children (MIS-C), autoimmune complications (from neurological conditions to the development of type I diabetes mellitus) and prolonged COVID.
Let's take a closer look at these complications.

Multisystemic inflammatory syndrome (MIS-C) associated with COVID-19: occurs in 0.1% of children who become infected and may require admission to intensive care in up to 68% of cases for mechanical ventilation or inotropics. It is important to note that most of those who suffer this complication are previously healthy.

Alterations are observed at cardiac level. The most common are mitral valve insufficiency, alterations in the wall of the left ventricle and coronary arteries. It is very infrequent to see this form of presentation at present, it was observed at the beginning of the pandemic, prior to the incorporation of pediatric vaccines.

Debut diabetes mellitus: the incidence of diabetes has been reported to be 31% higher for those with COVID-19 compared to those without COVID-19. Children under 18 years of age with COVID-19 are at higher risk of developing DBT 30 days after infection compared to those without COVID-19 and those with other viral infections.

Neurological complications: these are more common in hospitalized children, and more frequent if they also had C-IMS. Older children and those with pre-existing conditions were at higher risk. The most common symptoms were headache, convulsions, dizziness, delirium and encephalopathy.

Another reported complication of infection is long COVID which occurs in at least 5-10% of pediatric patients. It is a spectrum of multisystemic manifestations that persists for several months after the initial infection. Although the manifestations are more frequent in those with symptomatic or severe acute forms, they have also been described in children with asymptomatic symptoms or those who were infected with few symptoms. In general, they do not last more than 3 months, but may be prolonged in some cases.

Among the symptoms described in pediatrics are fatigue, shortness of breath, general malaise, cognitive dysfunction, impact on daily activities such as attendance, school performance and socialization with peers, among others. One of the main questions we ask ourselves is how to prevent the appearance of this complication, which has a great social, economic and mental health impact on the children who suffer from it.

Vaccination seems to be the best tool, as it causes less organ involvement of the infection and therefore the disease has a milder course, less duration of symptoms and less risk of prolonged COVID. In addition, an immune system with a more robust response due to vaccination would be more likely to fight the virus and get rid of viral particles faster, decreasing chronic inflammation and therefore the persistence of symptoms.

Vaccination is then presented, together with other factors (such as no underlying diseases, good function of the thymus and the whole immune system, microbiome, etc.), as a protective factor to prevent prolonged COVID.

Remember also that newborns can become infected with COVID-19 during labor or through exposure to sick caregivers after delivery. Infection is more severe in the pregnant mother: they are at greater risk of requiring intensive care, mechanical ventilation, cardiovascular replacement therapy and pre-eclampsia.

In addition, the newborns of these mothers have a higher risk of being premature, higher fetal mortality, miscarriages, congenital abnormalities and low birth weight. For this reason, vaccination against COVID-19 is very important in pregnant women, together with other vaccines such as influenza, tetanus, whooping cough and the recently incorporated vaccination against respiratory syncytial virus (RSV). In the case of vaccination for COVID-19 in pregnant women, it has been shown to protect both the newborn and the mother from complications.

COVID-19 vaccines have been shown to be effective in preventing SARS-CoV-2 infection both in the short term and for its later complications. The favorable impact of vaccination has been confirmed in both adults and pediatric patients globally.

The recommendations of the international societies of pediatrics and infectious diseases are based on the fact that the benefit of vaccination far outweighs the potential risks and, even when vaccinated persons may become infected, the clinical picture tends to be milder, with less possibility of prolonged manifestations and with the development of a potentially more robust and long-lasting immunity that has positive effects on the development of its complications and even on transmission among other children.
One of the main reasons for immunizing children against SARS-CoV-2 is to prevent complications, of which MIS-C is one of the most important. After the introduction of vaccines initially in adults and later in adolescents and children, the incidence of MIS-C has been gradually decreasing in many countries of the world and Chile has been one of the first countries to report the impact of vaccination on this complication.

It is particularly important to promote vaccination of immunosuppressed children and those with other relevant risk conditions (obesity, diabetes, asthma, congenital heart disease, genetic conditions, disorders affecting the nervous system or metabolism) since they are the ones who will have the most complications, hospitalization and risk of death if they acquire the infection.

COVID-19 vaccines based on the mRNA technology platform have proven to be the most efficient in preventing SARS-CoV-2 infection in the short term and the relevant disease in the longer term. They also have the advantage of being able to be developed more quickly and adjusted to the viral variants that emerge over time.

WHO (World Health Organization) recommends vaccination against COVID-19 as a key primary prevention tool. The vaccine helps to reduce viral circulation, hospitalizations and deaths related to COVID-19. It is true that they are not 100% effective in preventing infection, and that the action of the vaccine is not immediate as at least 2 weeks are required to achieve adequate defenses and be protected. It is also important to receive all doses, including boosters to achieve good antibody levels.

Evidence from the millions of children and adolescents who have been vaccinated demonstrates that vaccines against COVID-19 reduce the risk of infection and serious illness.

After clinical studies demonstrated that the vaccines were safe and effective in adults, studies were conducted in thousands of children and no serious safety problems were detected. The evidence is clear that the benefit of increased protection against serious illness or death far outweighs the risk of serious side effects.

Regulatory bodies such as the National Administration of Drugs, Food and Medical Technology (ANMAT) in Argentina, the U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC), along with independent safety experts, continue to closely monitor the safety of vaccines.

Remember that although vaccination is recommended in our country for all children older than 6 months, there are certain medical conditions that could increase the risk of a child suffering from a severe form of COVID-19, so vaccination should be prioritized in them, in addition to children under 1 year of age who have a higher risk of becoming seriously ill with COVID-19 than older children.