Study examining SARS-CoV-2 variant reinfection in children

In a recent study published in Journal of Pediatric Infectious Diseasesresearchers characterized children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection, determined the number of reinfections, and characterized the interval between the two infections in a patient population. rice field.

study: SARS-CoV-2 reinfection with different SARS-CoV-2 subspecies in children in Ohio, USA. Image Credit: FamVeld/Shutterstock.com

Background

Studies from the early stages of the coronavirus disease 2019 (COVID-19) pandemic suggested that protection from infection-acquired immunity persisted for more than 6 months and reinfection was rare.

Nevertheless, increasing data indicate increased reinfection rates associated with SARS-CoV-2 Omicron variants, with shorter reinfection intervals among Omicron variants.

About research

In the present study, researchers characterized SARS-CoV-2 reinfection in children. Individuals under the age of 21 who have been diagnosed as positive for SARS-CoV-2 nucleic acid Amplification (NAAT) or antigen Testing in any area of ​​the Nationwide Children’s Hospital (NCH) system from March 14, 2020 to September 30, 2022 was included.

Reinfection was defined as two positive tests that occurred before January 2022 or two positive tests that occurred at least 45 days after January 2022.

Samples testing positive for NAAT between January 2021 and September 2022 have been identified. We selected convenient samples from these for variant typing by mutation-specific reverse transcription-polymerase chain reaction (RT-PCR) assays.

Positive samples were screened for SARS-CoV-2 alpha, delta, or omicron BA.1. The H655Y assay was developed to screen for SARS-CoV-2 Omicron BA.2 or BA.4/5.

If samples were not available (for variant typing), the dominant SARS-CoV-2 variant at the time of sampling was assumed to be present in the specimens. Demographic data, testing locations, admission and immunization status were obtained from electronic health records (EHR).

Kruskal-Wallis and chi-square tests were performed to analyze continuous and categorical variables, respectively.

findings

Overall, researchers documented 27,244 positive tests during the study period. Of these, 541 reinfected patients were identified and included in the analysis. 539 patients had his 2nd infection and 2 had hers 3rd infection.

The median age of patients at the time of the second infection was 7.85 years. 56 patients were younger than 1 year. Nearly half of the reinfected patients were male.

EHR was available/accessible for 529 patients. Most patients (54%) had underlying medical conditions, with chronic dyspnea being most common at 16%.

About 13% were obese or overweight. Genetic/neurological disorders were observed in her 13% of subjects. Twenty-seven subjects were immunocompromised. Hospitalization rates were higher for primary infections (6%).

Vaccination status was available for only 69 patients, all of whom were fully vaccinated prior to reinfection. Of these, 16 were boosted at least two weeks before his second infection. Three were hospitalized and two were admitted to the intensive care unit (ICU).

The median time between two positive reactions was 229 days. Most reinfections (93%) occurred at least 90 days apart, and 7% occurred within 90 days of the initial infection.

Three patients had samples available from the first and second infection for variant typing. They were infected with SARS-CoV-2 delta and then Omicron BA.1 within 90 days. Over 1,800 samples were tested for variant monitoring.

By mid-December 2021 it increased to 45, increasing sharply until early February 2022, reaching 263 before BA.2 appeared.

The number of reinfections continues to rise, reaching 541 in September 2022. Reinfections accounted for 0.14%, 0.73%, 2.4%, 6.9%, and 6.4% of cumulative infections among predelta, delta, BA.1, and BA.2. , and BA.4/5 periods, respectively. Patients reinfected with BA.1 were significantly older than those infected with other variants.

No significant differences by variant type were observed in gender and hospitalization/ICU admission rates at the time of second infection.

The median time between two infections differed significantly by variant type. Of her two girls who were infected three times, one was 9 years old and had no underlying medical conditions. She was already one obese and she was 6.6 years old. They were not hospitalized with her COVID-19.

Conclusion

In short, researchers documented SARS-CoV-2 reinfection in pediatric patients and identified 541 cases of reinfection. Our findings demonstrate short reinfection intervals and high reinfection rates with SARS-CoV-2 Omicron variants. Hospitalization rates for reinfection were low.

Although reinfection rates increased after the emergence of SARS-CoV-2 Delta, a significant surge in reinfections was not observed until January 2022.

Notably, one-third of patients reinfected with BA.2 or BA.4/5 had a previous BA.1 infection, suggesting that BA.1 infection may not prevent reinfection. doing. A variety of variants caused most primary and secondary infections, but six patients were reinfected with the same variant (delta).

Above all, given continued viral evolution and increased vaccination coverage, surveillance of reinfection and assessment of the associated risks and disease burden in children are warranted.