Long-term immune response to SARS-CoV-2 infection and vaccination in children and adolescents

BACKGROUND

This analysis examined the durability of antibodies present after SARS-CoV-2 infection and vaccination in children and adolescents.

METHODS

Data were collected over 4 time points between October 2020-November 2022 as part of a prospective population-based cohort aged 5-to-19 years (N = 810). Results of the (1) Roche Elecsys® Anti-SARS-CoV-2 Immunoassay for detection of antibodies to the SARS-CoV-2 nucleocapsid protein (Roche N-test); and (2) qualitative and semi-quantitative detection of antibodies to the SARS CoV-2 spike protein receptor binding domain (Roche S-test); and (3) self-reported antigen/PCR COVID-19 test results, vaccination and symptom status were analyzed.

RESULTS

N antibody levels reached a median of 84.10 U/ml (IQR: 20.2, 157.7) cutoff index (COI) ~ 6 months post-infection and increased slightly to a median of 85.25 (IQR: 28.0, 143.0) COI at 12 months post-infection. Peak S antibody levels were reached at a median of 2500 U/mL ~6 months post-vaccination and remained for ~12 months (mean 11.6 months, SD 1.20).

CONCLUSIONS

This analysis provides evidence of robust durability of nucleocapsid and spike antibodies in a large pediatric sample up to 12 months post-infection/vaccination. This information can inform pediatric SARS-CoV-2 vaccination schedules.

IMPACT

This study provided evidence of robust durability of both nucleocapsid and spike antibodies in a large pediatric sample up to 12 months after infection. Little is known about the long-term durability of natural and vaccine-induced SARS-CoV-2 antibodies in the pediatric population. Here, we determined the durability of anti-SARS-CoV-2 spike (S-test) and nucleocapsid protein (N-test) in children/adolescents after SARS-CoV-2 infection and/or vaccination lasts at least up to 12 months. This information can inform future SARS-CoV-2 vaccination schedules in this age group.

SARS-CoV-2 Serostatus and COVID-19 Illness Characteristics by Variant Time Period in Non-Hospitalized Children and Adolescents

OBJECTIVE

To describe COVID-19 illness characteristics, risk factors, and SARS-CoV-2 serostatus by variant time period in a large community-based pediatric sample.

DESIGN

Data were collected prospectively over four timepoints between October 2020 and November 2022 from a population-based cohort ages 5 to 19 years old.

SETTING

State of Texas, USA.

PARTICIPANTS

Participants ages 5 to 19 years were recruited from large pediatric healthcare systems, Federally Qualified Healthcare Centers, urban and rural clinical practices, health insurance providers, and a social media campaign.

EXPOSURE

SARS-CoV-2 infection.

MAIN OUTCOME(S) AND MEASURE(S)

SARS-CoV-2 antibody status was assessed by the Roche Elecsys^® Anti-SARS-CoV-2 Immunoassay for detection of antibodies to the SARS-CoV-2 nucleocapsid protein (Roche N-test). Self-reported antigen or PCR COVID-19 test results and symptom status were also collected.

RESULTS

Over half (57.2%) of the sample (N = 3911) was antibody positive. Symptomatic infection increased over time from 47.09% during the pre-Delta variant time period, to 76.95% during Delta, to 84.73% during Omicron, and to 94.79% during the Omicron BA.2. Those who were not vaccinated were more likely (OR 1.71, 95% CI 1.47, 2.00) to be infected versus those fully vaccinated.

CONCLUSIONS

Results show an increase in symptomatic COVID-19 infection among non-hospitalized children with each progressive variant over the past two years. Findings here support the public health guidance that eligible children should remain up to date with COVID-19 vaccinations.

Incidence and predictors of breakthrough and severe breakthrough infections of SARS-CoV-2 after primary series vaccination in adults: A population-based survey of 22,575 participants

BACKGROUND

Breakthrough infections of SARS-CoV-2 are well-documented. The current study estimates breakthrough incidence across pandemic waves, and evaluates predictors of breakthrough and severe breakthrough infections (defined as those requiring hospitalization).

METHODS

89,762 participants underwent longitudinal antibody surveillance. Incidence rates were calculated using total person-days contributed. Bias-corrected and age-adjusted logistic regression determined multivariable predictors of breakthrough and severe breakthrough infection, respectively.

RESULTS

The incidence was 0.45 (0.38, 0.50) during pre-Delta, 2.80 (2.25, 3.14) during Delta, and 11.2 (8.80, 12.95) during Omicron, per 10,000 person-days. Factors associated with elevated odds of breakthrough included Hispanic ethnicity (vs non-Hispanic White, OR=1.243[1.073, 1.441]), larger household size (OR=1.251 [1.048, 1.494] for 3-5 vs. 1 and OR=1.726 [1.317, 2.262] for more than 5 vs. 1 person), rural vs urban living (OR=1.383 [1.122, 1.704]), receiving Pfizer or Johnson&Johnson vs. Moderna, and multiple comorbidities. Of the 1,700 breakthrough infections, 1,665 reported on severity; 112 (6.73%) were severe. Higher BMI, Hispanic ethnicity, vaccine type, asthma, and hypertension predicted severe breakthroughs.

CONCLUSION

Breakthrough infection was 4-25 times more common during the Omicron-dominant wave versus earlier waves. Higher burden of severe breakthrough infections was identified in subgroups.