https://orcid.org/0009-0006-5767-5414
Figures
Abstract
Background
Age is a crucial factor in COVID-19 risk and severity, however its role in humoral immunity is unclear. This study compares associations between age and immune response following COVID-19 vaccination and SARS-CoV-2 infection.
Methods
Data from the Arizona Healthcare, Emergency Response, and Other Essential Workers study (AZ-HEROES), a prospective cohort, were used to create two analytic groups: 1) a post-vaccination cohort including individuals who received two doses of the monovalent ancestral mRNA COVID-19 vaccine without prior SARS-CoV-2 infection; and 2) a post-infection cohort including unvaccinated individuals after primary infection. The analysis included data from September 2020 to April 2023. Children (<18 years) and adults (18 + years) were compared using linear regression, with immune response measured using log-transformed area under the curve (AUC) for receptor-binding domain (RBD) and spike protein subunit (S2). Finer age groups (<12, 12−17, 18−50, 50+) were also described. Adjusted models controlled for chronic conditions, medications, days since vaccination or infection, recent exposure to SARS-CoV-2 (post-vaccination only), strain type (post-infection only), and sociodemographic variables.
Results
The post-vaccination analysis included 749 participants, while the post-infection analysis included 203 participants. Participants were predominantly non-Hispanic White adults, with median ages of 43 and 40 years in the post-vaccination and post-infection cohorts, respectively. Most reported no chronic conditions. In adjusted post-vaccination analysis, adults had 7% higher RBD AUC (95% CI: 1.01–1.13) and 20% higher S2 AUC (95% CI: 1.13, 1.28) than children, although these results were attenuated when restricted to individuals taking the BNT162b2 vaccine only. Post-infection, adults had 22% higher S2 AUC (95% CI: 1.05, 1.40), while RBD differences were not significant. By finer age breakdown, adolescents (12−17 years) had stronger responses than children younger than 12 post-vaccination, with 26% higher RBD AUC (95% CI: 1.13–1.40) and 29% higher S2 AUC (95% CI: 1.14–1.46).
Conclusions
COVID-19 immune responses differ between children and adults, with adolescents exhibiting stronger immune response to vaccination than children younger than 12, however vaccine dosage may play a role in this observed difference. Age-related differences after infection were limited to S2 antibody responses.
Citation: Hawkes BA, Hollister J, Porter C, Lyski ZL, Burgess JL, Lutrick K, et al. (2026) Age-specific humoral immune response to SARS-CoV-2: A comparative analysis of antibody levels in children and adults after vaccination with primary series or infection. PLoS One 21(9): e0356178. https://doi.org/10.1371/journal.pone.0356178
Editor: Eleonora Nicolai, UniCamillus: Saint Camillus International University of Health and Medical Sciences, ITALY
Received: March 4, 2026; Accepted: July 30, 2026; Published: September 2, 2026
Copyright: © 2026 Hawkes et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: Data cannot be shared publicly because they are owned by the CDC and contain potentially identifiable participant information collected under informed consent agreements and human-subject protections that restrict unrestricted public release. Data are available upon request pending approval from the CDC for researchers who meet the criteria for access to confidential data. Requests for de-identified data can be sent to LTO7@cdc.gov.
Funding: Funding was provided by federal funds from the National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention under contract numbers 75D30120R68013 awarded to Marshfield Clinic Research Laboratory and 75D30120C08379 to University of Arizona. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Introduction
The manifestation of Coronavirus Disease 2019 (COVID-19) varies significantly between adults and children, with children generally exhibiting milder symptoms and better prognoses compared to adults [1–3]. For most infectious diseases, the most vulnerable age groups include the very young and the very old, however COVID-19 has not reflected this typical pattern. Although approximately 6% of the United States population is made up of children 5 years and younger, fewer than 0.1% of COVID-19 deaths are from this population, even though more than 90% of children under 4 have tested positive for previous or current infection by SARS-CoV-2 [4].
The effect that age has on the SARS-CoV-2 specific antibody response to infection and vaccination is variable across the literature. Some studies showed elevated pediatric response to vaccination [5–7] and infection [3,6,8–10] compared to adults. Others reported elevated antibody responses in adults to vaccination [11] and infection [12,13]. There are also studies showing a comparable response in children and adults, both post-vaccination [5,14] and post-infection [14,15]. One study reported 37.0% of children with positive SARS-CoV-2 PCR results demonstrated immunoglobulin G (IgG) seroconversion, compared to 76.2% of adults in the study [12]. However, a separate study reported significantly higher and more persistent SARS-CoV-2-specific IgG and neutralization activity over a 6-month period in children (6 months-18 years old) compared to adults (18−54 years old) [6]. Existing research is often limited in sample size, making these differences even harder to distinguish. These mixed findings indicate a need for more robust estimates of immune response in larger cohorts to clarify how age affects SARS-CoV-2 immune response. Understanding the key differences in immune response by age could help to guide future vaccination and public health strategies. While age-related differences in COVID-19 severity are well established, how humoral immune responses to SARS-CoV-2 infection or vaccination differ by age remains unclear.
The Arizona Healthcare, Emergency Response, and Other Essential Workers Study (AZ HEROES) was a prospective cohort that actively surveilled front line workers for SARS-CoV-2 infection and immunologic response to infection and vaccination. Frontline workers included those who could not socially distance during the peak of the COVID-19 pandemic due to their jobs, including health care workers, first responders, food service workers, childcare workers, and more [16]. This cohort was used to compare SARS-CoV-2 specific antibody responses in children and adults, as well as more granular categories to further explore the role of age. Our overall objective was to examine antibody responses following completion of primary mRNA COVID-19 vaccine series and SARS-CoV-2 infection in unvaccinated individuals. Here, we aimed to contribute to the understanding of how age influences SARS-CoV-2 immune responses. We hypothesized that SARS-CoV-2 humoral immune responses following vaccination and infection would differ across age groups.
Methods
Study design
For this study, two cohorts were nested within the AZ HEROES prospective cohort study. This included a cohort made up of frontline workers 18 years and older, and a cohort of children aged 6 months to 17 years. Frontline worker enrollment and data collection began in July 2020, and incorporated children in July 2021. Both cohorts were followed longitudinally to assess SARS-CoV-2 infection and COVID-19 vaccination status.
Across both cohorts, baseline surveys were completed at enrollment to capture sociodemographic information, social behaviors, health insurance status, medical history (including underlying medical conditions, daily medications, and vaccine history), and history of SARS-CoV-2 infection. Participants (or parents/guardians) were asked whether they had tested positive for SARS-CoV-2 prior to enrollment and, if so, to provide the date or approximate date of their positive test. COVID-19 vaccination status was collected at enrollment or when participants became eligible to receive the vaccine and was updated through periodic follow-up surveys. Vaccination data was verified via vaccination cards.
Participants from both cohorts provided a mid-turbinate nasal specimen weekly and at the onset of COVID-19-like illness symptoms throughout followup. Specimens were tested for SARS-CoV-2 at the Marshfield Clinic Laboratory (Marshfield, WI) using real time reverse transcription-polymerase chain reaction (rRT-PCR). Data collection ended April 2023.
Adult cohort
Beginning in July 2020, frontline workers in Arizona were enrolled and followed as part of the AZ HEROES Study [17]. Eligible adult participants were individuals working at least 20 hours per week in occupations requiring frequent direct contact with individuals outside their household during the COVID-19 pandemic. In addition to shared baseline measures, adult participants provided occupational characteristics.
Child cohort
In July 2021, the HEROES network was expanded to include children aged 6 months to 17 years. Informed consent was obtained from parents or legal guardians, and children aged 7–17 years provided assent to participate.
Ethical approval
All study protocols were approved by the University of Arizona Institutional Review Board (IRB) (protocol #2006729444), and informed consent was obtained from all participants.
Data collection
Blood collection.
All enrolled adult participants had the option to provide a blood sample at enrollment, following SARS-CoV-2 infection, after receiving any COVID-19 vaccine, every 11–13 weeks, and at the end of the study. Children had the option to provide a blood sample at enrollment, following SARS-CoV-2 infection, after receiving any COVID-19 vaccine, and at the end of the study. Children providing a blood draw required consent from a parent or guardian. To capture peak antibody response following vaccination or infection, this analysis was limited to participants who provided blood samples 14–60 days after completing the primary vaccine series or after a first-time SARS-CoV-2 infection. At each time point, 5–10 mL of whole blood was collected and processed according to CDC guidelines for serum collection [18]. Samples were frozen, transported on dry ice, and used for the serological assays detailed below [18].
Enzyme-linked immunosorbent assay (ELISA)
All serum samples were sent to the University of Arizona Genetics Core laboratory for semiquantitative ELISA testing against SARS-CoV-2 Washington-1 (WA1) receptor-binding domain (RBD) and S2, following established protocols [19,20]. Five threefold dilutions of sera were made starting at a 1:60 dilution and ending at 1:4860. An area under the serial dilution curve (AUC) was calculated using the optical density values at each dilution. AUC values represent a weighted sum of the optical density value at each dilution [21]. Whole genome sequencing was conducted on a subset of samples against Omicron (BA.2) RBD if eligible (cycle threshold value <30) [22]. Both RBD and S2 antibody can measure an individual’s immune response to a SARS-CoV-2 infection or COVID-19 vaccination, however the RBD test specifically detects antibodies that block the virus from attaching to cells, whereas the S2 test detects antibodies targeting the structural region responsible for fusing the virus into the cell [23,24]. Optical density was measured at five 3-fold dilutions starting at 1:60, and antibody levels were quantified as the area under the serial dilution curve (AUC). The AUC method is widely recognized for summarizing semiquantitative ELISA results, offering improved coverage probabilities of titration curves compared to other metrics, such as end-point titer [19,25,26].
Inclusion and exclusion criteria
The post-vaccination analysis for this study included data collected from December 16, 2020 to September 7, 2022, as this encompassed the timeframe in which vaccinations were available and a sample of individuals still had not had a primary SARS-CoV-2 infection. Participants were included in the post-vaccination analysis if they had received at least two doses of the monovalent BNT162b2 vaccine or the mRNA-1273 vaccine and had a blood draw 14–60 days after vaccination. They were excluded from the analytic sample set if they had been previously infected with SARS-CoV-2, received a non-mRNA COVID-19 vaccine, received a bivalent or non-ancestral COVID-19 vaccine, or were missing covariate data.
The post-infection analysis included data collected from September 24, 2020 to April 14, 2023, the dates that included unvaccinated participants with a first-time infection. Participants were included in the post-infection analysis if they had a first-time SARS-CoV-2 infection during the study period and a blood draw 14–60 days afterwards. They were excluded from the analytic sample if they had received a COVID-19 vaccine prior to blood collection or were missing covariate data. A supplementary analysis of vaccinated individuals was conducted for only those vaccinated with monovalent BNT162b2.
Statistical methods
Outcomes of interest.
The primary outcomes of interest were the AUC values for RBD and S2 antibodies obtained from ELISA assays for both the post-infection and post-vaccination cohorts. The AUC values were natural log-transformed prior to analysis [25]. Exponentiated beta coefficients from linear regression models were then reported, representing the geometric mean ratio (GMR). In this context, the GMR quantifies the proportional change in AUC values for RBD and S2 antibodies post-infection or vaccination.
Exposure of interest.
The primary exposure of interest was age group, defined as children younger than 18 years old and adults 18 years and older. To further examine age and antibody response, we also broke down age groups further: children less than 12 years, adolescents 12–17 years, adults 18–50 years, and adults older than 50 years. The age of children was broken down by difference in vaccine dosage, [27] while adults were divided based on cut-offs defined in the literature as important in terms of immune system decline among working-age adults [28].
Covariates.
For all adjusted analyses, covariates of interest were determined a priori based on existing literature [6,29]. They included sex, city of participant’s address, household size, race and ethnicity, body mass index (BMI) category, chronic conditions (binary variable, yes/no), daily medication use, and days since event. Chronic diseases included asthma, chronic lung disease, cancer, diabetes, heart disease, hypertension, immunosuppression, kidney disease, liver disease, neurologic or neuromuscular disease or disorder, and autoimmune disease. These conditions were identified using questionnaire data indicating whether participants had received medical care for any of these conditions within the past 12 months. Household size was included as a covariate due to its potential to influence exposure intensity and, therefore, viral load [30,31]. Vaccine manufacturer was excluded as a covariate due to sparse data among children, but a supplementary analysis limited to just those who received BNT162b2 was conducted to assess potential differences in antibody response by manufacturer.
For post-infection individuals, SARS-CoV-2 variant was also considered. Variant of infection was confirmed by whole-genome sequencing for eligible specimens or estimated by using the state-specific predominant variant at the time of infection according to Centers for Disease Control and Prevention data. For analysis, strain was categorized as “Omicron” and “Other.”
Due to limited data availability, race and ethnicity were grouped into a binary variable (“Non-Hispanic White” and “Other”), and BMI categories were simplified into “Underweight/Normal Weight” and “Overweight/Obese.” Covariates were selected a priori and assessed for collinearity. For children, BMI-for-age percentiles were used to define BMI categories [32]. These variables were included as potential confounders of the association between age and antibody response and were not evaluated as primary exposures of interest.
Demographics by age group
The association between demographics and age group were examined in the two cohorts, post-infection and post-vaccination. These were assessed using χ [2], Fisher exact, and t tests. Differences were considered statistically significant at p < 0.05.
Age group and antibody response
RBD and S2 were first compared by age and infection status (infection or vaccination) to identify potential differences. Unadjusted linear regression models and models fully adjusted for the covariates above were used to examine the relationship between age group and immune markers in two groups: vaccinated individuals and those previously infected with SARS-CoV-2. Since AUC values were transformed for analysis, exponentiated beta coefficients were reported, representing the geometric mean ratio. A sensitivity analysis restricted to BNT162b2 recipients was conducted to evaluate whether associations between age and antibody response were consistent when all participants received the same vaccine. All analyses were conducted using SAS OnDemand for Academics, R version 4.3.3, and GraphPad Prism software (version 9.4.1 for Mac; GraphPad Software). BMI for age percentile in children were calculated using the R package “cdcanthro” [33].
Results
Baseline demographic characteristics: Post-SARS-CoV-2 vaccination participants
After the exclusion criteria were applied, 749 participants remained in the post-vaccination primary analysis (Fig 1). The sample included 91 children and 658 adults and was predominantly female (64.1%), non-Hispanic White (75.9%), located in Tucson (61.2%), and without chronic conditions (73.5%). All children received the BNT162b2 vaccine series, whereas adults received either BNT162b2 (63.8%) or mRNA-1273 (36.2%).
This figure outlines the number of individuals eliminated from the AZHEROES cohort before the post-vaccination analysis.
Several participant characteristics differed significantly between children and adults. As expected, adults had a higher prevalence of chronic conditions, daily medication use, and overweight/obesity than children. They were also more likely to be female, have a smaller house size, have less days since vaccination. Location also differed between children and adults, with children more likely to be from Tucson or Phoenix, compared to other places in Arizona. Race and ethnicity distributions were similar between groups. See Table 1 for details.
Baseline demographic characteristics: Post-SARS-CoV-2 infection participants
For post-infection participants, 203 individuals were included in the primary analysis after exclusion criteria were applied (Fig 2). This sample was mostly non-Hispanic white (71.4%) from Tucson (57.6%), without chronic conditions (74.9%), not taking daily medications (59.6%), and infected with a non-Omicron variant (71.4%). There were 60 children and 143 adults in this sample. Complete summary statistics for post-infection participants are shown in Table 1. See Supplementary Table 2 for a further breakdown by age.
This figure outlines the number of individuals eliminated from the AZHEROES cohort before the post-infection analysis.
Adults had a higher prevalence of chronic conditions (84.3% vs 15.7%), daily medication use (89.0% vs 11.0%), and overweight/obesity (91.7% vs 8.3%) compared with children. In contrast, children lived in larger households on average (mean = 4.6 vs 3.3 people). Sex and location distributions were similar between groups (Table 1).
Antibody response by age group: Stratified by infection history
Post-infection and post-vaccination RBD AUC values differed significantly, while S2 AUC values did not. RBD AUC values, irrespective of age, were higher in vaccinated individuals compared to infected (P = 0.0007). However, S2 AUC values were not significantly different (slope P = 0.01, elevation P = 0.83). See S1 Fig for more information.
Antibody Response by Age Group: Post-Vaccination
Before adjusting for confounding variables, adults had a significantly higher antibody response compared to children following vaccination (Table 2). Specifically, RBD AUC was 12% higher in adults (95% CI: 1.07–1.18), while S2 AUC was 32% higher (95% CI: 1.24–1.40).
After adjusting for potential confounders, post-vaccination, RBD AUC was 7% higher in adults (95% CI: 1.01–1.13) and S2 AUC was 20% higher (95% CI: 1.13–1.28). Findings were generally similar in the sensitivity analysis restricted to BNT162b2 recipients, although effect estimates were attenuated (Supplementary Table 1).
When analyzed with narrower age categories, further differences in humoral immune response differences by age were revealed (Table 3). In post-vaccination individuals, children less than 12 years of age consistently had the lowest immune response, both in unadjusted and adjusted RBD and S2 AUC models. Compared to children younger than 12, RBD AUC values were 26%, 14%, and 5% high after adjustment in adolescents (12−17 years), adults (18−50 years), and older adults (50 + years), respectively. However, these differences were non-significant among older adults (95% CIs: 1.13–1.40, 1.07–1.21, 0.98–1.12). S2 AUC values varied slightly, with values 29%, 25%, and 22% higher after adjustment in adolescents, adults, and older adults, respectively, compared to children younger than 12 (95% CIs: 1.14–1.46, 1.17–1.35, 1.13–1.32).
Antibody Response by Age Group: Post-Infection
We found that adults had a significantly higher antibody response compared to children younger than 18 following infection in an unadjusted analysis (Table 2). Post-infection, RBD was 61% higher in adults (95% CI: 1.27–2.04) and S2 AUC was 27% higher (95% CI: 1.11–1.46). After adjustment, RBD AUC was 21% higher, although not significantly different, in adults (95% CI: 0.95–1.54) and S2 AUC was 22% higher (95% CI: 1.05–1.40).
The response observed in post-infection individuals varied slightly when breaking down age categories further. For example, after adjustment children younger than 12 and adolescents had similar RBD AUC (95% CI: 0.53–1.29), while adults had an RBD AUC 11% higher than children younger than 12 (95% CI: 0.84–1.47) and older adults 8% higher (95% CI: 0.78–1.49). None of these differences were statistically significant. After adjustment, S2 responses compared to children younger than 12 were similar to adolescents (95% CI 0.76–1.31), and older adults (95% CI: 0.88–1.31). Similarly, although these differences were observed, none were statistically significant. However, the highest response was seen in adults, 21% higher than children younger than 12 (95% CI 1.02–1.44).
Discussion
This study suggests that age is an important factor in SARS-CoV-2 antibody responses. Notably, both vaccination and infection yielded a higher response in adults compared to children, although this difference was limited to the S2 antibody resonse post-infection. RBD and S2 AUC values were significantly higher in adults before and after adjusting for potential confounders. However, once age was broken down into subcategories, the relationship was not as clear. There was more variation in response to vaccination compared to infection, although this is consistent with age-specific vaccine dosing schedules.
In June 2022, the Centers for Disease Control and Prevention (CDC) had recommended COVID-19 vaccination for all individuals over 6 months of age [34]. For individuals who are not moderately or severely immunocompromised, the BNT162b2 vaccine (Pfizer-BioNTech) was recommended at the following dosages: 3 µg for ages 6 months through 4 years, 10 µg for ages 5 years to 11 years, and 30 µg for ages 12 years and older [27]. For the mRNA-1273 vaccine (Moderna), the following dosages were recommended: 25 µg for ages 6 months through 11 years and 50 µg for ages 12 years and older [27].
Children younger than 12 consistently had the lowest immune response post-vaccination, followed by older adults, younger adults, and then adolescents. It is interesting to note the difference between children younger than 12 and adolescents, considering both age groups made up the category of children in our primary analysis. Because vaccine dosage varies systematically by age in pediatric populations, the observed differences between children younger than 12 years and adolescents may reflect age-related immunologic differences, vaccine dosage differences, or a combination of both. Our study design does not allow these effects to be separated. At age 12, individuals receive the same dose as adults (30 µg) compared to children aged 6 months through 4 years who receive 3 µg and children 5–11 years who receive 10 µg. Post-infection, children younger than 12 and adolescents had the lowest immune response, followed by older adults and then younger adults. Reduced antibody titers observed in older adults is consistent with the existing literature that establishes strong evidence in the loss of immune competence with age [35,36]. The similarity seen between children younger than 12 and adolescents post-infection that is not observed post-vaccination could be in part due to differences in age-specific vaccine dosing schedules. Regardless, it is interesting to note that while adolescents demonstrated the highest immune response post-vaccination, their response post-infection was one of the lowest. These findings suggest that age-related differences in humoral immune responses are nuanced and may differ across stages of development. The particularly strong responses observed among adolescents following vaccination highlight the importance of considering age-specific immune responses when evaluating vaccine performance and designing future immunization strategies.
Although these findings are consistent with past studies, [6,8–10,12–14] observing a difference between children and adult SARS-CoV-2 immune responses, most of the prior studies observed a higher immune response in children, contrasting this study. Many previously conducted studies have relatively low sample sizes (between 25 and 125 participants), so it is possible that some of the differences observed were due to lack of statistical power. However, of the two studies identified that had comparable samples to this study (669 participants and 842 participants), both indicated higher immune response in children [6,7].It is difficult to make direct comparisons between these studies, however, due to variations in study design. For example, one looked at immune response to COVID-19 vaccination using IgG titers, and did not eliminate or differentiate analysis based on if an individual had a SARS-CoV-2 infection prior to vaccination [7]. Considering that hybrid immunity usually results in much higher antibody titers than vaccination only, it is not surprising that results were inconsistent [37]. The other study was able to break down age group categories further, including age groups less than 5, 5–11, and 12–17 years [6]. They also did not have participants older than 54 years old included in the study. Timing of specimen collection is also an important factor to consider; this study looked at IgG response one month and 6 months post-infection or vaccination, whereas our data did not extend further than 60 days post-infection or vaccination. At the one-month time point, there was no significant difference in spike-specific IgG levels between age groups following infection. However, spike-specific IgG levels after vaccination were significantly higher in children aged less than 5 years old compared to children 12–17 years old and adults. Because our study measured ELISA-derived RBD and S2 area-under-the-curve values rather than spike-specific IgG titers, and because our analyses were limited to samples collected within 60 days of infection or vaccination, direct comparisons should be interpreted cautiously. Due to data availability, we also could not look at children less than 5 years old as an individual group.
This study has several unique strengths. To date, most studies comparing SARS-CoV-2 immune response in adults and children have low sample sizes. Our larger sample size allowed us to compare these two age groups with greater statistical power and break down our age groups into more granular categories to explore the nuance in these differences. The frequent collection of participant serum samples allowed us to specifically look at responses within 14–60 days of an event (either vaccination or infection), which allowed for consistency when comparing immune responses. This study also self-confirmational assays interrogating antibodies against two separate domains of the spike protein to further enhance our findings. Finally, following enrollment in AZ-HEROES, participants underwent weekly SARS-CoV-2 PCR testing and frequent vaccination surveys. This rigorous monitoring ensured that blood draws included in the analysis were unlikely to violate exclusion criteria, such as those occurring after a repeat SARS-CoV-2 infection or an additional COVID-19 vaccine.
Several limitations should be considered. First, immune responses were only evaluated within 60 days of infection or vaccination, excluding the assessment of age-related differences over time. Although participants with known prior SARS-CoV-2 infection were excluded from the post-vaccination analysis, asymptomatic infections may have resulted in exposure misclassification since pre-vaccination serologic screening was not performed. We also did not evaluate hybrid immunity. Additionally, ELISA measured binding antibodies but did not assess neutralizing activity or T-cell responses. Although the overall sample size was large, relatively few children, especially those younger than 12 years, and fewer post-infection participants limited statistical power for subgroup analyses. Residual confounding is also possible, as not all comorbidities and potential confounders could be accounted for. Selection bias may have occurred because blood collection was voluntary, particularly among children, and the cohort consisted primarily of healthy individuals with mild infections. Finally, because the study was conducted in Arizona, the findings may not be generalizable to other populations.
The primary purpose of this study was to evaluate differences in antibody responses to SARS-CoV-2 infection and vaccination by age. Humoral antibody levels have been shown to be a crucial factor in SARS-CoV-2 infection and reinfection, so understanding what factors effect these levels is crucial. We highlighted differences that exist between children and adults but also highlighted how the age groups among children may be of especially high importance. Understanding immune responses post-vaccination is beneficial for providing well-supported vaccine recommendations for different age groups. Additionally, providing details of immune response to the SARS-CoV-2 infection to the public will help with more precise COVID-19 messaging. Much of the COVID-19 pandemic brought confusion among the public due to several unknowns. An added layer of understanding immune response is an important step in having a more complete understanding of the disease and therefore being able to communicate that understanding with the public in a precise way. Future research should focus on more granular age categories, especially in children. Immunity changes over time and hybrid immunity should be evaluated to be more reflective of the general population today.
Supporting information
S1 Fig. Differences in Antibody AUC values by Age.
Antibody AUC values were compared between adults and children against RBD and S2 of WA-1 spike. P values are based on Mann-Whitney non-parametric test.
https://doi.org/10.1371/journal.pone.0356178.s001
(TIF)
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