Reinfection with SARS-CoV-2 in children

Until the last few months, the coronavirus disease 2019 (COVID-19) pandemic had the least impact on children. However, there is still much to be said about how infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects children and how previous infections protect children from reinfection. You need to understand.

study: Burden of SARS-CoV-2 and protection from symptomatic secondary infections in children.. Image Credit: Rimma Bondarenko / Shutterstock

This is even more important as they are likely to be vaccinated last in all groups. The new preprint examines these questions in a cohort of children in Managua, Nicaragua.

Background

Most children have mild or asymptomatic infections with SARS-CoV-2, but some have developed severe symptoms such as shortness of breath and multisystem inflammatory syndrome (MIS-C). This is common in youngest and oldest children and children with comorbidities. They also have the highest risk of acute sequelae of COVID-19 (PASC) and are also called “long covids”, but the risk is much lower than in adults.

Asymptomatic and mild infections in this age group are largely overlooked because SARS-CoV-2 infections in children are mainly studied in the context of hospitalized children. Most such studies have been conducted in high-income countries, limiting their potential for generalization.

Previous studies have shown that even if bactericidal immunity declines rapidly, previous infections continue at stable levels and the virus can become endemic. This can make the infection as serious as the human coronavirus infection, which is a seasonal endemic disease that is currently prevalent. The big question is how long does this take to happen?

Research is also underway to understand how the severity of various degrees of illness is associated with protective immunity against sequelae and subsequent reinfection. In addition, the impact of the recently emerging variant of concern on clinical disease in children has not yet been evaluated. Current research is medRxiv* The preprint server will try to answer these questions.

What did the study show?

This study used data from the Nicaragua Pediatric Influenza Cohort collected from March 1, 2020 to October 15, 2021. It was designed as a prospective study and included about 2,000 non-immunocompromised children aged 0-14 years.

Previously infected children need a positive anti-SARS-CoV-2 receptor binding domain (RBD) and spike antibody test, or at least real-time confirmation of infection by reverse transcriptase-polymerase chain reaction (RT-PCR). was. 60 days before the current episode. All symptomatic cases must be confirmed by RT-PCR and had a history of hospitalization within 28 days of onset of symptoms.

All cases were classified as asymptomatic, mild, moderate, or severe. People with respiratory symptoms were considered to have a moderate illness, and those who required hospitalization were said to have a severe illness.

Reinfection is a positive RT-PCR test after a previous confirmed infection due to a positive enzyme-linked immunosorbent assay (ELISA) and / or a positive previous PCR result. It was defined as a positive PCR test more than 60 days later. All children who tested positive for the ELISA test with no evidence of current infection were retrospectively evaluated for the severity of the infection.

During the calm period from August 1, 2020 to February 15, 2021, no cases were considered COVID-19 unless there was a clear epidemiological association with the source of infection.

In this study, half of the children were seropositive during the study and there were about 200 PCR-positive COVID-19 cases. Of these, 12 children had to be hospitalized due to illness. The incidence was highest under 2 years of age, 16 per 1,000 person-years. This was three times higher than any other age group and twice the overall incidence of 7.7 cases per 100 man-years.

About one-fifth of symptomatic infections occur in previously infected children and have a slightly higher incidence among older children. By the age of 5, 60% of children were protected from symptomatic reinfection, compared with 64% and about 50% of children aged 5-9 and 10-14, respectively.

All reinfections occurred in 2021 and were caused by the gamma and delta variant (VOC) of SARS-CoV-2, which began to prevail in the country during this period. The same trends as for the entire group were observed with age.

The incidence of infection in children appears to be high, with more than half of children having seroconversion during the study period. Although most were mild or asymptomatic infections, children under the age of 2 were five times more likely to be at risk of serious illness than children between the ages of 5 and 9. However, overall, only 6% developed severe illness, with an incidence of 0.4 per 100 man-years.

Approximately one-tenth of patients with confirmed COVID-19 had long covids, primarily associated with respiratory symptoms that lasted more than 28 days. These included runny nose, cough, and sometimes stuffy nose and sore throat. One child under the age of two was breathing rapidly.

What is the impact?

These findings support previous reports that COVID-19 is less frequent and more severe in children than in adults. Of all SARS-CoV-2 infections in this age group, only a few are detected by PCR, emphasizing the need for community-based prospective studies to understand the course of these infections. I am.

The increased frequency of flat tires in children under 5 years and the oldest may be due to the high incidence of symptomatic and severe infections in these groups. The lowest protection appeared to be in children under the age of 10. Unlike previous studies, about 1 in 10 children with confirmed infections have been infected for a long time, and most children have respiratory problems rather than common symptoms.

The results also show that symptomatic reinfection is relatively common, accounting for more than one-fifth of all infections found in children. Some of these were serious illnesses. This indicates the need to monitor the severity of SARS-CoV-2 infections in children and the need for safe vaccines to prevent punctures and severe reinfections in youngest children. ..

*Important Notices

medRxiv publishes unpeer-reviewed preliminary scientific reports and should not be considered definitive, guide clinical / health-related behaviors, or be treated as established information.