Long-term Immune Response to SARS-CoV-2 Infection Among Children and Adults After Mild Infection

SARS-CoV-2 Antibody Kinetics in Unvaccinated Hospitalized Children With COVID-19

BACKGROUND

Antibody levels decline a few months post-acute COVID-19, but humoral memory persists in adults. Age and disease severity may affect antibody responses. This study aims to evaluate the presence and durability of antibody responses in children with COVID-19.

METHODS

A prospective, single-center study, involving unvaccinated children 0-16 years of age who were hospitalized with COVID-19 between October 2020 and December 2021, was conducted. Serological testing for anti-Spike severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG and neutralizing antibodies was performed at diagnosis and at 1-, 3-, 6- and 12-months post-infection.

RESULTS

A total of 65 immunocompetent children were enrolled [mean age (±SD): 6.7 (±6.4) years; males: 56.9%]. At 3 months, 40/44 (91%) children were seropositive; seropositivity persisted in 22/26 (85%) children at 6 months and in 10/12 (83%) children at 12 months. There was no evidence that age was modifying the prediction of variance of SARS-CoV-2 IgG levels. In contrast, SARS-CoV-2 IgG levels varied with time and disease severity. The association with time was non-linear, so that with increasing time there was a significant reduction in SARS-CoV-2 IgG levels [coef, 0.044 (95% confidence interval {CI}: 0.061-0.028), P < 0.001]. For each increment of time, the higher disease severity group was associated with 0.9 lower SARS-CoV-2 IgG levels. Everyone varied from the average effect of time with an SD of 0.01, suggesting that individuals may have different trajectories across time.

CONCLUSION

Disease severity, but not age, influences antibody titers among children hospitalized with COVID-19. SARS-CoV-2 infection induces durable seroconversion in these children with detectable IgG levels at 1 year after infection.

Anti_spike and anti_nucleocapsid IgG responses to SARS-CoV-2 in children of Jordan

Background

It is proven that children have significantly milder COVID-19 disease compared to adults. Various immunological characteristics influence this age-related difference in protection against COVID-19. Pediatric COVID-19 in Jordan is extremely under reported.

Objectives

The primary goal of this work is to identify the anti_S and anti_N antibody responses in a random group of children in Jordan and compare it to that of naturally infected-unvaccinated adults.

Methods

151 unvaccinated children, 4 days to 18 years old, were screened for anti_S and anti_N antibodies. History of COVID-19 infection or exposure to infection and symptom severity were reported by parents on a special questionnaire.

Results

78.9 % and 65.3 % of participants were seropositive for anti_S IgG and anti_N Abs, respectively. There was a remarkable association between age and anti_S IgG and anti_N IgG antibody titers, as children aged 12 years or older had increased anti_S IgG titers (mean = 19.3 BAU/mL) compared to younger groups (means of 10.15, 9.24, 7.91 BAU/mL for age groups 6-12, 1-6, less than 1 year, respectively). Gender did not show a statistically important role in anti_S and anti_N IgG seropositivity rates or titers. Children displayed significantly elevated anti_S titers (mean = 13.23 BAU/mL) compared to naturally infected adults (mean = 9.72 BAU/mL), in contrast, adults' anti_N titers (mean = 39.64 U/mL) were significantly higher compared to those of children (mean = 10.77 U/mL).

Conclusions

The current work provides evidence of distinctly robust and persistent humoral immunity displayed by high anti_S and anti_N IgG in children, even >12 months post-infection. Age was the only factor that had a significant statistical impact on anti_S and anti_N Ab levels among the pediatric group in this study. Children exhibited significantly higher anti_S titers than naturally infected adults. In contrast, adults' anti_N titers were significantly higher. Such information can assist direct pediatric SARS-CoV-2 immunization programs, with implications for creating age-targeted strategies for diagnostic and population protection measures.

SARS-CoV-2 seroprevalence among children in Greece during Omicron variant period

The Omicron variant is associated with increased transmissibility, but evidence about the impact of Omicron in seropositivity of children is limited. This study aims to evaluate SARS-CoV-2 seroprevalence in children during the different variants' subperiods. A prospective multicenter seroprevalence study was conducted in 7 University public hospitals in Greece from November 2021 to August 2022 (3 subperiods: November 2021-February 2022, March 2022-May 2022, June 2022-August 2022). Children from different age groups, admitted to the hospital or examined in outpatient clinics for reasons other than COVID-19 were enrolled. Neutralizing antibodies (Nabs), anti-Spike (anti-S) and anti-nucleocapsid (anti-N) SARS-CoV-2 IgG in serum were evaluated. A total of 2127 children (males:57,2%; median age:4,8years) were enrolled. Anti-N IgG seropositivity increased from 17,8% in the first sub-period to 40,7% in the second sub-period and then decreased in the third sub-period (36,7%). Anti-S IgG seropositivity appeared to have an increasing trend over the study period, starting from 34,8% and reaching 80,7%. Children aged 1-4 years old have significantly higher anti-N IgG titers compared to children aged 0-1 years old (p < 0,001). Infants have significantly lower anti-S IgG titers compared to all other age groups (p < 0,001). Immunocompromised children and infants have the lowest seropositivity for NAbs.Conclusions During the Omicron period, seropositivity significantly increased, as a result of higher transmissibility. Neonates and infants have lower antibody titers compared to other age groups, while young children aged 1-4 years old present higher antibody titers, suggesting that this age group may mount a higher antibody response. Continuous surveillance seroprevalence studies are needed in children, in order to identify the true extent of SARS-CoV-2 and guide the planning of adequate public health measures.

Dynamics of anti-SARS-CoV-2 IgG antibody responses following breakthrough infection and the predicted protective efficacy: A longitudinal community-based population study in China

OBJECTIVES

To assess the dynamics of the anti-SARS-CoV-2 IgG antibody levels and their efficacy against COVID-19.

METHODS

We conducted a longitudinal serological analysis of 852 breakthrough COVID-19 infections among the community-based population in Yichang, China. Anti-SARS-CoV-2 IgG levels were measured by chemiluminescence at approximately 3, 4, and 9 months after infection. A linear mixed model predicted IgG antibody decline over 18 months. The effectiveness of antibodies in preventing symptomatic and severe infections was determined using an existing meta-regression model.

RESULTS

IgG antibodies slowly declined after breakthrough infections. Initially high at around 3 months (339.44 AU/mL, IQR: 262.78-382.95 AU/mL), levels remained significant at 9 months (297.74 AU/mL, IQR: 213.22-360.62 AU/mL). The elderly (≥60 years) had lower antibody levels compared to the young (<20 years) (P < 0.001). The protective efficacy of antibodies against symptomatic and severe infections was lower in the elderly (≥60 years) (78.34% and 86.33%) compared to the young (<20 years) (96.56% and 98.75%) after 1 year.

CONCLUSION

The study indicated a slow decline in anti-SARS-CoV-2 IgG antibodies, maintaining considerable efficacy for over 1 year. However, lower levels in the elderly suggest reduced protective effects, underscoring the need for age-specific vaccination strategies.

Risk of SARS-CoV-2 Reinfection in Children Within the 12 Months Following Mild COVID-19: Insights From a Survey Study

Understanding the correlation between immune response and protection from COVID-19 will play a pivotal role in predicting the effectiveness of vaccines in children. We studied SARS-CoV-2 reinfection risk in children 12 months post-mild COVID-19. Children under 5 years old exhibited lower reinfection risk than older infected or vaccinated siblings during 12 months postimmunization.

Analytical and clinical evaluations of SNIBE Maglumi chemiluminescent immunoassay for the detection of SARS-CoV-2 antigen in salivary samples

OBJECTIVES

In this study, we describe the analytical and clinical performances of the SNIBE Maglumi SARS-CoV-2 antigen fully-automated chemiluminescent immunoassay (MAG-CLIA) on salivary samples.

METHODS

Limit of detection (LOD), linearity and precision were tested for values close to or below the declared LOD. Clinical performance of MAG-CLIA was evaluated on leftover salivary samples from the healthcare workers (HCW) surveillance program, at the University-Hospital of Padova. Salivary samples were analyzed by Lumipulse G SARS-CoV-2 Ag, and in case where the values exceeded 0.41 ng/L, further testing was conducted using TaqPathTM COVID-19 RT-PCR (Applied Biosystems, Thermo Fisher Scientific).

RESULTS

The estimated MAG-CLIA LOD was 3 ng/L, with repeatability of 7.5 %. Good linearity was demonstrated by diluting two samples at 52.7 ng/L and 211.4 ng/L. Of the 228 HCW samples, 59/228 (25.9 %) were positive, 169/228 (74.1 %) were negative. MAG-CLIA SARS-CoV-2 sAg median level (and interquartile range [IQR]) was 5.03 ng/L (<0.001-35.8 ng/L) for positive and <0.001 ng/L (<0.001 ng/L) for negative samples. MAG-CLIA AUC was 0.795 (95 % CI: 0.720-0.871). Using the best cut-off, 3.5 ng/L, sensitivity and specificity were 57.1 % (95 % CI: 42.2-71.2 %) and 97.0 % (95 % CI: 93.2-99.0 %), respectively. The agreement with the molecular assay was 88.1 % (Cohen's kappa 0.606 [SE=0.066, p<0.001]).

CONCLUSIONS

The analytical performances of MAG-CLIA are satisfactory, also when values below LOD were tested. In saliva samples, although specificity was elevated, clinical performance was not comparable with that on nasopharyngeal swabs (NPS).

Comparisons of Pediatric and Adult SARS-CoV-2-Specific Antibodies up to 6 Months after Infection, Vaccination, or Hybrid Immunity

BACKGROUND

Characterization of longitudinal SARS-CoV-2-specific antibody responses in children following infection and vaccination is needed to inform SARS-CoV-2 vaccine policy decisions for children, which may differ from adults.

METHODS

We enrolled individuals at the time of SARS-CoV-2 infection or vaccination for longitudinal serological testing and compared SARS-CoV-2-spike-specific IgG and neutralization activity in children and adults stratified by infection and vaccination status using enzyme-linked immunosorbent and virus neutralization assays.

RESULTS

Between June 2020 and December 2022, we collected sera from 669 participants aged 40 days to 55 years, including 330 unvaccinated individuals with laboratory-confirmed SARS-CoV-2 infection, 180 vaccinated SARS-CoV-2-naïve individuals, and 159 vaccinated previously infected individuals. Half (n = 330, 49.3%) were children. SARS-CoV-2-specific IgG and neutralization activity in children < 12 years old in response to infection persisted at higher levels than those of adults through at least 6 months (spike-specific IgG levels, 2.05 [95% CI: 1.4-3.1] times higher than adults; neutralizing activity, median 88.8 vs 75.2%, respectively, p = .04). In addition, all pediatric participants had significantly higher IgG levels compared with adults at 6 months following infection or vaccination, regardless of prior infection status. Vaccine-induced SARS-CoV-2-specific IgG responses in previously infected individuals persisted at higher levels than those from infection alone at 6 months (median AUC, children 5-11 years old, 9115 vs 368; adolescents 3613 vs 475; adults 1956 vs 263, all p < .001).

CONCLUSIONS

These data demonstrate the robust and persistent immunologic response of SARS-CoV-2 vaccination in children and emphasize the benefit of vaccination after SARS-CoV-2 infection.

Stronger and durable SARS-CoV-2 immune response to mRNA vaccines in 5-11 years old children with prior COVID-19

BACKGROUND AND OBJECTIVES

mRNA vaccines elicit a durable humoral response to SARS-CoV-2 in adults, whereas evidence in children is scarce. This study aimed to assess the early and long-term immune response to the mRNA vaccine in children with or without previous SARS-CoV-2 infection.

METHODS

In a multicentre prospective observational study, we profiled the immune response to the Pfizer BioNTech (BNT162b2) vaccine in 5-11-year-old children attending the University Pediatric Hospital of Padua and Bambino-Gesù Hospital in Rome (Italy) from December-2021 to February-2023. Blood samples were collected pre-, 1-, and 6-months after vaccination. Neutralizing antibodies (NAbs) and anti-spike-receptor-binding-domain (anti-S-RBD) IgG titers were analyzed through Plaque Reduction Neutralization Test (PRNT) and chemiluminescent immune-enzymatic assay (CLIA), respectively. Immune cell phenotypes were analyzed by flow cytometry.

RESULTS

Sixty children (26 [43 %] female, median age = 8 years [IQR = 7-10.7]) were enrolled in the study, including 46 children with a laboratory-confirmed previous COVID-19 (SARS-CoV-2-recovered) and 14 SARS-CoV-2-naïve participants defined as the absence of antigen-specific antibodies before vaccination. SARS-CoV-2-recovered participants recorded higher anti-S-RBD IgG and Wild-type and Omicron BA.2 NAbs titers than SARS-CoV-2-naïve participants at both 1- and 6-months after vaccination. Antibody titers correlated with T (Tregs) and B (Bregs) regulatory cell frequencies in SARS-CoV-2-recovered children. Both SARS-CoV-2-recovered and SARS-CoV-2-naïve participants decreased antibody titers by approximately 100 to 250 % from 1 to 6 months. While children with immunocompromising underlying conditions developed immune responses comparable to those of healthy children, solid organ transplant recipients exhibited lower levels of NAbs and anti-S-RBD IgG titers, as well as reduced frequencies of Tregs and Bregs.

CONCLUSIONS

mRNA vaccination triggered a higher production of specific anti-SARS-CoV-2 antibodies along with increased levels of regulatory cells in children with previous SARS-CoV-2 infection up to the following 6 months. These findings provide insights into boosting pre-existing immunity.

Serosurveillance among urban slum and non-slum populations immunized with COVID-19 vaccines in Bangladesh

Using two rounds of serosurveillance, we aimed to observe the COVID-19 vaccination status and the dynamics of antibody responses to different vaccines among urban slum and non-slum populations of Bangladesh. Adults (>18 years) and children (10-17 years) were enrolled in March and October 2022. Data including COVID-19 vaccine types and dosage uptake were collected. SARS-CoV-2 spike (S)-specific antibodies were measured in blood. The proportion of vaccinated children was significantly lower among slum than non-slum populations. Two doses of vaccines showed an increase in the level of anti-S-antibodies up to 2 months, followed by reduced levels at 2-6 months and a resurgence at 6-12 months. Children showed significantly higher anti-S-antibodies after two doses of the Pfizer-BioNTech vaccine than adults; however, after 6 months, the level of antibodies declined in younger children (10 - < 12 years). In a mixed vaccine approach, mRNA vaccines contributed to the highest antibody response whether given as the first two doses or as the third dose. Our findings emphasized the need for increasing the coverage of COVID-19 vaccination among slum children and booster dosing among all children. The use of mRNA vaccines in the mixed vaccination approach was found to be useful in boosting the antibody response to SARS-CoV-2.

Clinical and Analytical Performance of ELISA Salivary Serologic Assay to Detect SARS-CoV-2 IgG in Children and Adults

Saliva is a promising matrix with several purposes. Our aim is to verify if salivary anti-SARS-CoV-2 antibody determination is suitable for monitoring immune responses. One hundred eighty-seven subjects were enrolled at University-Hospital Padova: 105 females (56.1%) and 82 males (43.9%), 95 (50.8%) children and 92 (49.2%) adults. Subjects self-collected saliva using Salivette; nineteen subjects collected three different samples within the day. A serum sample was obtained for all individuals. The N/S anti-SARS-CoV-2 salivary IgG (sal-IgG) and serum anti-SARS-CoV-2 S-RBD IgG (ser-IgG) were used for determining anti-SARS-CoV-2 antibodies. The mean (min-max) age was 9.0 (1-18) for children and 42.5 (20-61) for adults. Of 187 samples, 63 were negative for sal-IgG (33.7%), while 7 were negative for ser-IgG (3.7%). Spearman's correlation was 0.56 (p < 0.001). Sal-IgG and ser-IgG levels were correlated with age but not with gender, comorbidities, prolonged therapy, previous SARS-CoV-2 infection, or time from last COVID-19 infection/vaccination. The repeatability ranged from 23.8% (7.4 kAU/L) to 4.0% (3.77 kAU/L). The linearity of the assay was missed in 4/6 samples. No significant intrasubject differences were observed in sal-IgG across samples collected at different time points. Sal-IgG has good agreement with ser-IgG. Noninvasive saliva collection represents an alternative method for antibody measurement, especially in children.

Neutralizing Antibody Levels as a Correlate of Protection Against SARS-CoV-2 Infection: A Modeling Analysis

Although anti-severe acute respiratory syndrome-coronavirus 2 antibody kinetics have been described in large populations of vaccinated individuals, we still poorly understand how they evolve during a natural infection and how this impacts viral clearance. For that purpose, we analyzed the kinetics of both viral load and neutralizing antibody levels in a prospective cohort of individuals during acute infection with alpha variant. Using a mathematical model, we show that the progressive increase in neutralizing antibodies leads to a shortening of the half-life of both infected cells and infectious viral particles. We estimated that the neutralizing activity reached 90% of its maximal level within 11 days after symptom onset and could reduce the half-life of both infected cells and circulating virus by a 6-fold factor, thus playing a key role to achieve rapid viral clearance. Using this model, we conducted a simulation study to predict in a more general context the protection conferred by pre-existing neutralization titers, due to either vaccination or prior infection. We predicted that a neutralizing activity, as measured by 50% effective dose > 103 , could reduce by 46% the risk of having viral load detectable by standard polymerase chain reaction assays and by 98% the risk of having viral load above the threshold of infectiousness. Our model shows that neutralizing activity could be used to define correlates of protection against infection and transmission.

Cohort profile: evaluation of immune response and household transmission of SARS-CoV-2 in Costa Rica: the RESPIRA study

PURPOSE

The RESPIRA cohort aims to describe the nature, magnitude, time course and efficacy of the immune response to SARS-CoV-2 infection and vaccination, population prevalence, and household transmission of COVID-19.

PARTICIPANTS

From November 2020, we selected age-stratified random samples of COVID-19 cases from Costa Rica confirmed by PCR. For each case, two population-based controls, matched on age, sex and census tract were recruited, supplemented with hospitalised cases and household contacts. Participants were interviewed and blood and saliva collected for antibodies and PCR tests. Participants will be followed for 2 years to assess antibody response and infection incidence.

FINDINGS TO DATE

Recruitment included 3860 individuals: 1150 COVID-19 cases, 1999 population controls and 719 household contacts from 304 index cases. The age and regional distribution of cases was as planned, including four age strata, 30% rural and 70% urban. The control cohort had similar sex, age and regional distribution as the cases according to the study design. Among the 1999 controls recruited, 6.8% reported at enrolment having had COVID-19 and an additional 12.5% had antibodies against SARS-CoV-2. Compliance with visits and specimens has been close to 70% during the first 18 months of follow-up. During the study, national vaccination was implemented and nearly 90% of our cohort participants were vaccinated during follow-up.

FUTURE PLANS

RESPIRA will enable multiple analyses, including population prevalence of infection, clinical, behavioural, immunological and genetic risk factors for SARS-CoV-2 acquisition and severity, and determinants of household transmission. We are conducting retrospective and prospective assessment of antibody levels, their determinants and their protective efficacy after infection and vaccination, the impact of long-COVID and a series of ancillary studies. Follow-up continues with bimonthly saliva collection for PCR testing and biannual blood collection for immune response analyses. Follow-up will be completed in early 2024.

TRIAL REGISTRATION NUMBER

NCT04537338.

Comparative study showed that children faced a 78% higher risk of new-onset conditions after they had COVID-19

AIM

Children have largely been unaffected by severe COVID-19 compared to adults, but data suggest that they may have experienced new conditions after developing the disease. We compared outcomes in children who had experienced COVID-19 and healthy controls.

METHODS

A retrospective nested cohort study assessed the incidence rate of new-onset conditions after COVID-19 in children aged 0-14 years. Data were retrieved from an Italian paediatric primary care database linked to Veneto Region registries. Exposed children with a positive nasopharyngeal swab were matched 1:1 with unexposed children who had tested negative. Conditional Cox regression was fitted to estimate the adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for the exposure and outcome associations after adjusting for covariates.

RESULTS

We compared 1656 exposed and 1656 unexposed children from 1 February 2020 to 30 November 2021. The overall excess risk for new-onset conditions after COVID-19 was 78% higher in the exposed than unexposed children. We found significantly higher risks for some new conditions in exposed children, including mental health issues (aHR 1.8, 95% CI 1.1-3.0) and neurological problems (aHR 2.4, 95% CI 1.4-4.1).

CONCLUSION

Exposed children had a 78% higher risk of developing new conditions of interest after COVID-19 than unexposed children.

Persistent humoral immune response in youth throughout the COVID-19 pandemic: prospective school-based cohort study

Understanding the development of humoral immune responses of children and adolescents to SARS-CoV-2 is essential for designing effective public health measures. Here we examine the changes of humoral immune response in school-aged children and adolescents during the COVID-19 pandemic (June 2020 to July 2022), with a specific interest in the Omicron variant (beginning of 2022). In our study "Ciao Corona", we assess in each of the five testing rounds between 1874 and 2500 children and adolescents from 55 schools in the canton of Zurich with a particular focus on a longitudinal cohort (n=751). By July 2022, 96.9% (95% credible interval 95.3-98.1%) of children and adolescents have SARS-CoV-2 anti-spike IgG (S-IgG) antibodies. Those with hybrid immunity or vaccination have higher S-IgG titres and stronger neutralising responses against Wildtype, Delta and Omicron BA.1 variants compared to those infected but unvaccinated. S-IgG persist over 18 months in 93% of children and adolescents. During the study period one adolescent was hospitalised for less than 24 hours possibly related to an acute SARS-CoV-2 infection. These findings show that the Omicron wave and the rollout of vaccines boosted S-IgG titres and neutralising capacity. Trial registration number: NCT04448717. https://clinicaltrials.gov/ct2/show/NCT04448717 .

Fading SARS-CoV-2 humoral VOC cross-reactivity and sustained cellular immunity in convalescent children and adolescents

Cross-reactive cellular and humoral immunity can substantially contribute to antiviral defense against SARS-CoV-2 variants of concern (VOC). While the adult SARS-CoV-2 cellular and humoral immunity and its cross-recognition potential against VOC is broadly analyzed, similar data regarding the pediatric population are missing. In this study, we perform an analysis of the humoral and cellular SARS-CoV-2 response immune of 32 convalescent COVID-19 children (children), 27 convalescent vaccinated adults(C + V+) and 7 unvaccinated convalescent adults (C + V-). Similarly to adults, a significant reduction of cross-reactive neutralizing capacity against delta and omicron VOC was observed 6 months after SARS-CoV-2 infection. While SAR-CoV-2 neutralizing capacity was comparable among children and C + V- against all VOC, children demonstrated as expected an inferior humoral response when compared to C + V+. Nevertheless, children generated SARS-CoV-2 reactive T cells with broad cross-recognition potential. When compared to V + C+, children presented even comparable frequencies of WT-reactive CD4 + and CD8 + T cells with high avidity and functionality. Taking into consideration the limitations of study - unknown disease onset for 53% of the asymptomatic pediatric subjects, serological detection of SARS-CoV-2 infection-, our results suggest that following SARS-CoV-2 infection children generate a humoral SARS-CoV-2 response with neutralizing potential comparable to unvaccinated COVID-19 convalescent adults as well a sustained SARS-CoV-2 cellular response cross-reactive to VOC.

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.

Infants and young children generate more durable antibody responses to SARS-CoV-2 infection than adults

As SARS-CoV-2 becomes endemic, it is critical to understand immunity following early-life infection. We evaluated humoral responses to SARS-CoV-2 in 23 infants/young children. Antibody responses to SARS-CoV-2 spike antigens peaked approximately 30 days after infection and were maintained up to 500 days with little apparent decay. While the magnitude of humoral responses was similar to an adult cohort recovered from mild/moderate COVID-19, both binding and neutralization titers to WT SARS-CoV-2 were more durable in infants/young children, with spike and RBD IgG antibody half-life nearly 4X as long as in adults. IgG subtype analysis revealed that while IgG1 formed the majority of the response in both groups, IgG3 was more common in adults and IgG2 in infants/young children. These findings raise important questions regarding differential regulation of humoral immunity in infants/young children and adults and could have broad implications for the timing of vaccination and booster strategies in this age group.

Comparing SARS-CoV-2 variants among children and adolescents in Germany: relative risk of COVID-19-related hospitalization, ICU admission and mortality

PURPOSE

SARS-CoV-2 infections cause COVID-19 and have a wide spectrum of morbidity. Severe disease courses among children are rare. To date, data on the variability of morbidity in relation to variant of concern (VOC) in children has been sparse and inconclusive. We compare the clinical severity of SARS-CoV-2 infection among children and adolescents in Germany during the Wildtype and Alpha combined, Delta and Omicron phases of the COVID-19 pandemic.

METHODS

Comparing risk of COVID-19-related hospitalization, intensive care unit (ICU) admission and death due to COVID-19 in children and adolescents, we used: (1) a multi-center seroprevalence study (SARS-CoV-2-KIDS study); (2) a nationwide registry of pediatric patients hospitalized with SARS-CoV-2 infections; and (3) compulsory national reporting for RT-PCR-confirmed SARS-CoV-2 infections in Germany.

RESULTS

During the Delta predominant phase, risk of COVID-19-related hospitalization among all SARS-CoV-2 seropositive children was 3.35, ICU admission 1.19 and fatality 0.09 per 10,000; hence about halved for hospitalization and ICU admission and unchanged for deaths as compared to the Wildtype- and Alpha-dominant period. The relative risk for COVID-19-related hospitalization and ICU admission compared to the alpha period decreased during Delta [0.60 (95% CI 0.54; 0.67) and 0.51 (95% CI 0.42; 0.61)] and Omicron [0.27 (95% CI 0.24; 0.30) and 0.06 (95% CI 0.05; 0.08)] period except for the < 5-year-olds. The rate of case fatalities decreased slightly during Delta, and substantially during Omicron phase.

CONCLUSION

Morbidity caused by SARS-CoV-2 infections among children and adolescents in Germany decreased over the course of the COVID-19 pandemic, as different VOCs) emerged.

Atopy and Elevation of IgE, IgG3, and IgG4 May Be Risk Factors for Post COVID-19 Condition in Children and Adolescents

SARS-CoV-2 infection causes transient cardiorespiratory and neurological disorders, and severe acute illness is rare among children. Post COVID-19 condition (PCC) may cause profound, persistent phenotypes with increasing prevalence. Its manifestation and risk factors remain elusive. In this monocentric study, we hypothesized that atopy, the tendency to produce an exaggerated immunoglobulin E (IgE) immune response, is a risk factor for the manifestation of pediatric PCC. We present a patient cohort (n = 28) from an early pandemic period (2021-2022) with comprehensive evaluations of phenotypes, pulmonary function, and molecular investigations. PCC predominantly affected adolescents and presented with fatigue, dyspnea, and post-exertional malaise. Sensitizations to aeroallergens were found in 93% of cases. We observed elevated IgE levels (mean 174.2 kU/L, reference < 100 kU/L) regardless of disease severity. Concurrent Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) was found in 29% of patients that also faced challenges in school attendance. ME/CFS manifestation was significantly associated with elevated immunoglobulin G subclasses IgG3 (p < 0.05) and IgG4 (p < 0.05). A total of 57% of patients showed self-limiting disease courses with mean recovery at 12.7 months (range 5-25 months), 29% at 19.2 months (range 12-30 months), and the rest demonstrated overall improvement. These findings offer additional insights into immune dysregulation as a risk factor for pediatric PCC.

SARS-CoV-2 serology in pediatrics: Seroprevalence studies in unvaccinated children and humoral antibody response post vaccination

BACKGROUND

Humoral response against SARS-CoV-2 is increasingly accepted as the central correlate of immune protection. Recent pediatric seroprevalence data are extremely limited. Significant knowledge gaps also exist in immune response to mRNA SARS-CoV-2 vaccination in children. As children demonstrate distinct response to naïve infection relative to adults, it is essential to investigate age-specific differences in seroprevalence and antibody response to SARS-CoV-2 vaccination.

METHODS

Seroprevalence was assessed through two cross-sectional serosurveys prior to COVID-19 vaccination approval in children <5 years using residual patient specimens (n = 2902). To assess antibody response post-vaccination, 842 participants (580 children, 262 adults) were prospectively recruited with informed consent. Participation required completion of a health questionnaire and blood donation. Samples were collected at varying times post-vaccination and assayed using the Abbott AdviseDx SARS-CoV-2 IgG II and DiaSorin LIAISON SARS-CoV-2 TrimericS IgG assays.

RESULTS

Significant increases in seroprevalence were observed between the first and second serosurveys in unvaccinated children <6 months to 5 years (38-75%). In the prospective vaccination cohort, serokinetic response decreased with time post-dose of an mRNA vaccine. Measured IgG titres were significantly higher in children relative to adults across all time points.

CONCLUSIONS

This is the largest evaluation of quantitative SARS-CoV-2 antibody assays in a cohort of Canadian children, adolescents, and adults. Findings suggest high rates of SARS-CoV-2 exposure among unvaccinated young children in the Toronto community. Additional data supports children have higher antibody titres relative to adults post-vaccination.

Clinical features of COVID-19 in Italian outpatient children and adolescents during Parental, Delta, and Omicron waves: a prospective, observational, cohort study

Introduction

COVID-19 features changed with the Omicron variant of SARS-CoV-2 in adults. This study aims to describe COVID-19 symptoms in children and adolescents during the Parental, Delta, and Omicron eras.

Methods

A single-centre, prospective observational study was conducted on individuals aged 0-20 years attending the University Hospital of Padua (Italy) from April 2020 to December 2022. COVID-19 cases were defined by positive SARS-CoV-2 molecular detection and/or serology; patient/family symptoms and virological positivity were considered to determine the infection onset. Variables were summarized and compared using appropriate tests of descriptive statistics.

Results

A total of 509 cases [46% female, median age eight years (IQR: 4-12)] were studied. Three-hundred-eighty-seven (76%), 52 (10%), and 70 (14%) subjects experienced COVID-19 during the Parental, Delta, and Omicron waves, respectively. All subjects developed an asymptomatic/mild COVID-19. Overall, the most frequent symptoms were fever (47%) and rhinitis (21%), which showed a significant increasing incidence from the Parental to Omicron waves (p < 0.001). Conversely, diarrhea was most common during the pre-Omicron eras (p = 0.03). Stratifying symptoms according to the age group, fever, rhinitis, and skin rashes were observed more frequently among infants/toddlers; conversely, fatigue was more common in children older than five years. The duration of symptoms was similar across different SARS-CoV-2 variants of concern (VOCs); conversely, the number of symptoms varied according to the age group (p < 0.0001).

Discussion

This study showed differences in COVID-19 clinical presentation among infants, children, and adolescents and confirmed Omicron infection is more likely to be associated with upper respiratory symptoms. However, further population-based studies are needed to support these findings. In addition, active surveillance will play a crucial role in assessing the disease severity of future VOCs.

Cardiac Function Evaluation after SARS-CoV-2 mRNA Vaccination in Children and Adolescents: A Prospective Speckle-Tracking Echocardiography Study

BACKGROUND

Possible cardiac impairment after SARS-CoV-2 mRNA vaccination is a common driver of parental vaccine hesitancy. We performed a comprehensive echocardiographic evaluation of biventricular function in vaccinated children with or without previous COVID-19 compared to healthy controls.

METHODS

We conducted a single-center, prospective, case-control study enrolling children and adolescents aged 5-18 years attending the pediatric clinic of the University Hospital of Padua from April to June 2022. Three months after receiving the primary mRNA vaccination or booster dose, the patients underwent a cardiac assessment, including standard echocardiography and speckle-tracking echocardiography (STE). A pre-pandemic historical cohort of age- and gender-matched healthy children were used as a control.

RESULTS

A total of 39 post-VACCINE cases (24, 61% female), mean age 12.6 ± 2.6 years (range 8-17), were enrolled in the study. Ninety percent (N = 35) of patients were previously healthy. No differences in left ventricular diameters, left ventricular ejection fraction (LVEF), and tricuspid annular plane systolic excursion (TAPSE) were observed between cases and controls. Global longitudinal strain (GLS) was in the normal range in all individuals, with no differences between post-VACCINE cases and controls (-21.7 ± 2.3% vs. 21.2 ± 1.8%; p = 0.338). However, GLS was found to be slightly but significantly reduced in post-VACCINE children with a previous COVID-19 compared to naïve-vaccinated individuals (post-VACCINE+COVID-19: -19.9 ± 1.1% vs. post-VACCINE-only: -22.0 ± 2.3%; p = 0.002).

CONCLUSIONS

We did not observe an impairment in GLS or in other indices of LV structure or function after mRNA COVID-19 vaccination.

Infection-Induced Immunity Is Associated With Protection Against Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Decreased Infectivity

BACKGROUND

The impact of infection-induced immunity on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has not been well established. Here we estimate the effects of prior infection induced immunity in adults and children on SARS-CoV-2 transmission in households.

METHODS

We conducted a household cohort study from March 2020-November 2022 in Managua, Nicaragua; following a housheold SARS-CoV-2 infection, household members are closely monitored for infection. We estimate the association of time period, age, symptoms, and prior infection with secondary attack risk.

RESULTS

Overall, transmission occurred in 70.2% of households, 40.9% of household contacts were infected, and the secondary attack risk ranged from 8.1% to 13.9% depending on the time period. Symptomatic infected individuals were more infectious (rate ratio [RR] 21.2, 95% confidence interval [CI]: 7.4-60.7) and participants with a prior infection were half as likely to be infected compared to naïve individuals (RR 0.52, 95% CI:.38-.70). In models stratified by age, prior infection was associated with decreased infectivity in adults and adolescents (secondary attack risk [SAR] 12.3, 95% CI: 10.3, 14.8 vs 17.5, 95% CI: 14.8, 20.7). However, although young children were less likely to transmit, neither prior infection nor symptom presentation was associated with infectivity. During the Omicron era, infection-induced immunity remained protective against infection.

CONCLUSIONS

Infection-induced immunity is associated with decreased infectivity for adults and adolescents. Although young children are less infectious, prior infection and asymptomatic presentation did not reduce their infectivity as was seen in adults. As SARS-CoV-2 transitions to endemicity, children may become more important in transmission dynamics.

Infants and young children generate more durable antibody responses to SARS-CoV-2 infection than adults

Since the emergence of SARS-CoV-2, research has shown that adult patients mount broad and durable immune responses to infection. However, response to infection remains poorly studied in infants/young children. In this study, we evaluated humoral responses to SARS-CoV-2 in 23 infants/young children before and after infection. We found that antibody responses to SARS-CoV-2 spike antigens peaked approximately 30 days after infection and were maintained up to 500 days with little apparent decay. While the magnitude of humoral responses was similar to an adult cohort recovered from mild/moderate COVID-19, both binding and neutralization titers to WT SARS-CoV-2 were more durable in infants/young children, with Spike and RBD IgG antibody half-life nearly 4X as long as in adults. The functional breadth of adult and infant/young children SARS-CoV-2 responses were comparable, with similar reactivity against panel of recent and previously circulating viral variants. Notably, IgG subtype analysis revealed that while IgG1 formed the majority of both adults' and infants/young children's response, IgG3 was more common in adults and IgG2 in infants/young children. These findings raise important questions regarding differential regulation of humoral immunity in infants/young children and adults and could have broad implications for the timing of vaccination and booster strategies in this age group.

IgG antispike persistence and immunophenotype in children infected by SARS-CoV-2

AIM

The immune status of children recovering from SARS-CoV-2 infection is not completely understood. We describe IgG antispike persistence in children infected during the first two pandemic waves. In addition, we compared with healthy controls their leukocyte populations and CD64 expression.

METHODS

Cross-sectional study. Carried out from October 2021 to February 2022 in nonreinfected and nonvaccinated children with SARS-CoV-2 in 2020. The presence of antispike IgG was studied using chemiluminescent immunoassay. Leukocyte populations were analysed using flow cytometry and marked for CD45, CD4, CD8 and CD64. Statistical minor than 0.05 was considered significant.

RESULTS

One hundred and eighty-three control and 77 patients were included. IgG antispike determinations were performed after a median of 501 days (262-464); 52 of 77 children were positive. Cases showed significantly higher percentages of monocytes, lymphocytes, CD8⁺ and CD4⁺ . In addition, CD64 expression was higher in monocytes and neutrophils. The presence of IgG antispike was accompanied by a higher percentage of CD64⁺ neutrophils.

CONCLUSION

In our series, the SARS-CoV-2 IgG antispike protein was usually positive beyond 1 year after infection. Furthermore, leukocyte populations from cases differ from controls, with higher CD64 expression on neutrophils and monocytes. Prospective clinical observations are required to confirm the implications of these findings.

Understanding COVID-19 in children: immune determinants and post-infection conditions

Coronavirus disease 2019 in children presents with milder clinical manifestations than in adults. On the other hand, the presence of a wide range of inflammatory manifestations, including multisystem inflammatory syndrome in children (MIS-C), in the period after infection suggests a particular susceptibility of some children toward severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Both protective factors that prevent evolution to severe forms and risk factors for post-infectious conditions are likely to be found in age-related differences in the immune system. The prompt innate response with type I IFN production and the generation of neutralizing antibodies play a crucial role in containing the infection. The greater number of naive and regulatory cells in children helps to avoid the cytokine storm while the causes of the intense inflammatory response in MIS-C need to be elucidated. This review aims to analyze the main results of the recent literature assessing immune response to SARS-CoV-2 over the pediatric age group. We summarized such observations by dividing them into innate and acquired immunity, then reporting how altered immune responses can determine post-infectious conditions. IMPACT: The main immune markers of acute SARS-CoV-2 infection in children are summarized in this review. This paper reports a broad overview of age-related differences in the immune response to SARS-CoV-2 and emerging post-infection conditions. A summary of currently available therapies for the pediatric age group is provided.

Antibody Persistence After Primary SARS-CoV-2 Infection and Protection Against Future Variants Including Omicron in Adolescents: National, Prospective Cohort Study

BACKGROUND

Antibodies are a measure of immunity after primary infection, which may help protect against further SARS-CoV-2 infections. They may also provide some cross-protection against SARS-CoV-2 variants. There are limited data on antibody persistence and, especially, cross-reactivity against different SARS-CoV-2 variants after primary infection in children.

METHODS

We initiated enhanced surveillance in 18 secondary schools to monitor SARS-CoV-2 infection and transmission in September 2020. Students and Staff provided longitudinal blood samples to test for variant-specific SARS-CoV-2 antibodies using in-house receptor binding domain assays. We recruited 1189 students and 1020 staff; 160 (97 students, 63 staff) were SARS-CoV-2 nucleocapsid-antibody positive at baseline and had sufficient serum for further analysis.

RESULTS

Most participants developed sustained antibodies against their infecting [wild-type (WT)] strain as well as cross-reactive antibodies against the Alpha, Beta and Delta variants but at lower titers than WT. Staff had significantly lower antibodies titers against WT as cross-reactive antibodies against the Alpha, Beta and Delta variants than students (all P < 0.01). In participants with sufficient sera, only 2.3% (1/43) students and 17.2% (5/29) staff had cross-reactive antibodies against the Omicron variant; they also had higher antibody titers against WT (3042.5; 95% confidence interval: 769.0-12,036.2) than those who did not have cross-reactive antibodies against the Omicron variant (680.7; 534.2-867.4).

CONCLUSIONS

We found very high rates of antibody persistence after primary infection with WT in students and staff. Infection with WT induced cross-reactive antibodies against Alpha, Beta and Delta variants, but not Omicron. Primary infection with WT may not be cross-protective against the Omicron variant.

Molecular Determinants of the Early Life Immune Response to COVID-19 Infection and Immunization

Clinical manifestations from primary COVID infection in children are generally less severe as compared to adults, and severe pediatric cases occur predominantly in children with underlying medical conditions. However, despite the lower incidence of disease severity, the burden of COVID-19 in children is not negligible. Throughout the course of the pandemic, the case incidence in children has substantially increased, with estimated cumulative rates of SARS-CoV-2 infection and COVID-19 symptomatic illness in children comparable to those in adults. Vaccination is a key approach to enhance immunogenicity and protection against SARS-CoV-2. Although the immune system of children is functionally distinct from that of other age groups, vaccine development specific for the pediatric population has mostly been limited to dose-titration of formulations that were developed primarily for adults. In this review, we summarize the literature pertaining to age-specific differences in COVID-19 pathogenesis and clinical manifestation. In addition, we review molecular distinctions in how the early life immune system responds to infection and vaccination. Finally, we discuss recent advances in development of pediatric COVID-19 vaccines and provide future directions for basic and translational research in this area.

Children's SARS-CoV-2 Infection and Their Vaccination

SARS-CoV-2, a novel coronavirus, causes respiratory tract infections and other complications in affected individuals, and has resulted in numerous deaths worldwide. The unprecedented pace of its transmission worldwide, and the resultant heavy burden on healthcare systems everywhere, prompted efforts to have effective therapeutic strategies and vaccination candidates available to the global population. While aged and immunocompromised individuals form a high-risk group for COVID-19 and have severe disease outcome, the rate of infections among children has also increased with the emergence of the Omicron variant. In addition, recent reports of threatening SARS-CoV-2-associated complications in children have brought to the forefront an urgent necessity for vaccination. In this article, we discuss the current scenario of SARS-CoV-2 infections in children with a special focus on the differences in their immune system response as compared to adults. Further, we describe the various available COVID-19 vaccines, including the recent bivalent vaccines for children, in detail, intending to increase willingness for their acceptance.

Duration of immunity to SARS-CoV-2 in children after natural infection or vaccination in the omicron and pre-omicron era: A systematic review of clinical and immunological studies

Background

Duration of humoral and cellular memory in children previously infected SARS-CoV-2 or vaccinated and subsequent risk of reinfection is still not fully elucidated.

Methods

Systematic review of studies retrieved from medical databases and article reference lists.

Results

From 2420 identified articles, 24 met the inclusion criteria. Children infected during the pre-omicron era developed long lasting (at least 10-12 months) humoral and cellular immunity against pre-Omicron SARS-CoV-2 variants, but have reduced in vitro cross-reactivity against Omicron. Conversely, although vaccination has a limited efficacy in preventing new infection with pre-Omicron and Omicron variants, in vitro studies suggested that vaccine-induced immunity provides better in vitro cross-neutralization against pre-Omicron and Omicron variants. Preprints published after the period of inclusion of our review suggested that overall risk of infection after Omicron infection is reduced, but children developed weak neutralizing responses in about half cases.

Conclusions

Available evidence, although limited, suggested a long-lasting but unperfect protection of previous infections or vaccination against pre-Omicron and Omicron variants. Based on our findings, it might be reasonable to offer families of children infected before Omicron a booster vaccination. A similar indication should be proposed also for those infected with Omicron, specifically for more fragile children at higher risk of COVID-19-related complications, based on better cross-variant neutralisation induced by vaccination.

Systematic review registration

PROSPERO, identifier ID 353189.

Long-term persistence of IgG antibodies in recovered COVID-19 individuals at 18 months post-infection and the impact of two-dose BNT162b2 (Pfizer-BioNTech) mRNA vaccination on the antibody response: Analysis using fixed-effects linear regression model

This era of emerging variants needs a thorough evaluation of data on the long-term efficacy of immune responses in vaccinated as well as recovered individuals, to understand the overall evolution of the pandemic. In this study, we aimed to assess the dynamics of IgG response over 18 months in n = 36 patients from the Umbria region in Italy, who had a documented history of COVID-19 infection in March 2020, and then compared the impact of two-dose BNT162b2 (Pfizer-BioNTech) vaccination on the antibody responses of these patients with the ones who did not receive any dose of vaccine. This is the longest observation (March 2020-September 2021) for the presence of antibodies against SARS-CoV-2 in recovered individuals along with the impact of 2 dose-BNT162b2 vaccination on these responses. Fixed-effect regression models were used for statistical analysis which could be also used to predict future titer trends. At 18 months, 97% participants tested positive for anti-NCP hinting towards the persistence of infection-induced immunity even for the vaccinated individuals. Our study findings demonstrate that while double dose vaccination boosted the IgG levels in recovered individuals 161 times, this "boost" was relatively short-lived. The unvaccinated recovered individuals, in contrast, continued to show a steady decline but detectable antibody levels. Further studies are required to re-evaluate the timing and dose regimen of vaccines for an adequate immune response in recovered individuals.

SARS-CoV-2 infected children form early immune memory responses dominated by nucleocapsid-specific CD8+ T cells and antibodies

This is the third year of the SARS-CoV-2 pandemic, and yet most children remain unvaccinated. COVID-19 in children manifests as mostly mild or asymptomatic, however high viral titers and strong cellular and humoral responses are observed upon acute infection. It is still unclear how long these responses persist, and if they can protect from re-infection and/or disease severity. Here, we analyzed immune memory responses in a cohort of children and adults with COVID-19. Important differences between children and adults are evident in kinetics and profile of memory responses. Children develop early N-specific cytotoxic T cell responses, that rapidly expand and dominate their immune memory to the virus. Children's anti-N, but not anti-S, antibody titers increase over time. Neutralization titers correlate with N-specific antibodies and CD8+T cells. However, antibodies generated by infection do not efficiently cross-neutralize variants Gamma or Delta. Our results indicate that mechanisms that protect from disease severity are possibly different from those that protect from reinfection, bringing novel insights for pediatric vaccine design. They also underline the importance of vaccination in children, who remain at risk for COVID-19 despite having been previously infected.

Infection-induced immunity is associated with protection against SARS-CoV-2 infection, but not decreased infectivity during household transmission

Background

Understanding the impact of infection-induced immunity on SARS-CoV-2 transmission will provide insight into the transition of SARS-CoV-2 to endemicity. Here we estimate the effects of prior infection induced immunity and children on SARS-CoV-2 transmission in households.

Methods

We conducted a household cohort study between March 2020-June 2022 in Managua, Nicaragua where when one household member tests positive for SARS-CoV-2, household members are closely monitored for SARS-CoV-2 infection. Using a pairwise survival model, we estimate the association of infection period, age, symptoms, and infection-induced immunity with secondary attack risk.

Results

Overall transmission occurred in 72.4% of households, 42% of household contacts were infected and the secondary attack risk was 13.0% (95% CI: 11.7, 14.6). Prior immunity did not impact the probability of transmitting SARS-CoV-2. However, participants with pre-existing infection-induced immunity were half as likely to be infected compared to naïve individuals (RR 0.53, 95% CI: 0.39, 0.72), but this reduction was not observed in children. Likewise, symptomatic infected individuals were more likely to transmit (RR 24.4, 95% CI: 7.8, 76.1); however, symptom presentation was not associated with infectivity of young children. Young children were less likely to transmit SARS-CoV-2 than adults. During the omicron era, infection-induced immunity remained protective against infection.

Conclusions

Infection-induced immunity is associated with protection against infection for adults and adolescents. While young children are less infectious, prior infection and asymptomatic presentation did not reduce their infectivity as was seen in adults. As SARS-CoV-2 transitions to endemicity, children may become more important in transmission dynamics.

Article summary

Infection-induced immunity protects against SARS-CoV-2 infection for adolescents and adults; however, there was no protection in children. Prior immunity in an infected individual did not impact the probability they will spread SARS-CoV-2 in a household setting.

Perceived Psychological Impact on Children and Parents of Experiencing COVID-19 Infection in One or More Family Members

SARS-CoV-2 infection may impair behavior and mental health; we explored the psychological impact on parents and children who experienced COVID-19 within their families. A cross-sectional web-based survey was conducted on families attending the COVID-19 Follow-up Clinic at the Department for Women’s and Children’s Health, Padua (Italy). From April 2020 to August 2021, 75 surveys were collected from 66 families (97 parents and 129 children); almost 70% of participants had COVID-19, mostly asymptomatic/mildly symptomatic, and the median time from infection to survey compilation was 164.7 days (SD 56). Most parents (>87%) reported positive relationships with family members either before, during, or after COVID-19. More than one-third of children and adolescents were unable to adapt to isolation. Among 31 pre-school children with a median age of 3 (SD 1.7), a change of one or more functions was reported for 74.2% of cases irrespective of COVID-19 status, particularly a change in circadian rhythm (25%), in relationship with parents (42.8%), and poor emotional control (36%). Among 74 children with a median age of 10.9 years (SD 2.7), 8.1% had a score indicating a disease; however, significant impairment in attention was reported for 16.7%, along with anxiety/depression and problems with conduct in 5.6% and 6.5% of cases, respectively.

Case report: Exploring under the tip of the iceberg: A case series of "self-limiting" multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a serious condition triggered by SARS-COV-2 infection, characterized by persistent fever, multiorgan dysfunction, and increased inflammatory markers. It requires hospitalization and prompt treatment, with nearly 60% of the cases needing intensive care and 2% fatality rate. A wide spectrum of clinical characteristics and therapeutic approaches has been reported in MIS-C. We describe a series of four patients with MIS-C, defined according to the current case definitions, with a self-limiting course and no need for immunomodulatory treatment ("self-limiting MIS-C"). Few data about self-limiting MIS-C are available to date and no information on medium- and long-term outcome of this subset of patients has been reported. Although limited in size, our experience provides new insights into the MIS-C syndrome, highlighting an underestimated aspect of the disease that may have significant therapeutic implications.

Seroprevalence of SARS CoV-2 among children after the second surge (June 2021) in a rural district of South India: Findings and lessons from a population-based survey

OBJECTIVE

To determine the seroprevalence of SARS COV 2 among children in the Bangalore Rural district.

METHODS

We conducted a cross-sectional study after the second surge of COVID-19 from 14 June to 13 July 2021 and recruited 412 children through house to house visits from four villages in a rural district. We administered a questionnaire to collect demographics and details of COVID-19 infection and used the ABCHEK Antibody Card test (NuLifecare,India) which is an ICMR approved test for detecting antibodies (IgG & IgM) by immunochromatography using the finger prick method. We used Statistical Package for the Social Sciences version 20.0 for analysis.

RESULTS

Our participants had an age group ranging from 11 months to 18 years. There was an almost equal distribution of boys (48.3%) and girls (51.7%). We estimated seroprevalence of 45.9% (95% CI: 41-50.8) among children. Seroprevalence was significantly associated with a history of symptoms suggestive of COVID-19 in the past, the seropositive status of the parents, and any other family members being tested positive. Age and gender of the child, education and occupation of the parents were not associated with the seropositivity status of the child.

CONCLUSION

Seroprevalence of COVID-19 among children corresponds to adult seroprevalence during the same time interval. This knowledge can be of practical application where adult prevalence is documented. Unvaccinated children in low-resource settings need special attention with respect to monitoring for new mutations as well as managing endemic needs.