No abstract

COVID-19 manifests as a milder disease in children than adults, but the underlying mechanisms are not fully characterized. Here we assess the difference in cellular or humoral immune responses of pediatric and adult COVID-19 patients to see if these factors contribute to the severity dichotomy. Children’s non-specific immune profile is dominated by naive lymphocytes and HLA-DRhighCX3CR1low dendritic cells; meanwhile, children show strong specific antibody and T cell responses for viral structural proteins, with their T cell responses differing from adults by having weaker CD8+TNF+ T cells responses to S peptide pool but stronger responses to N and M peptide pools. Finally, viral mRNA is more abundant in pediatric patients. Our data thus support a scenario in which SARS-CoV-2 infected children contribute to transmission yet are less susceptible to COVID-19 symptoms due to strong and differential responses to the virus.

Epidemiological evidence that COVID-19 manifests as a milder disease in children compared to adults has been reported by numerous studies, but the mechanisms underlying this phenomenon have not been characterized. It is still unclear how frequently children get infected, and/or generate immune responses to SARS-CoV-2. We have performed immune profiling of pediatric and adult COVID-19 patients in Brazil, producing over 38 thousand data points, asking if cellular or humoral immune responses could help explain milder disease in children. In this study, pediatric COVID-19 patients presented high viral titers. Though their non-specific immune profile was dominated by naive, non-activated lymphocytes, their dendritic cells expressed high levels of HLA-DR and were low in CX3CR1, indicating competence to generate immune responses that are not targeted to inflamed tissue. Finally, children formed strong specific antibody and T cell responses for viral structural proteins. Children’s T cell responses differed from adults in that their CD8+ TNFα+ T cell responses were low for S peptide but significantly higher against N and M peptide pools. Altogether, our data support a scenario in which SARS-CoV-2 infected children may contribute to transmission, though generating strong and differential responses to the virus that might associate with protection in pediatric COVID-19 presentation.

Impacts of anthropogenic noise is an important but poorly studied aspect of wetland ecology. Many aquatic animals use sound to attract mates, coordinate movements, defend territory, and detect predators. However, anthropogenic noise (e.g., from boat or automobile motors) are increasingly important in wetlands. Therefore, it is important to understand how anthropogenic noise pollution affects these habitats. I sampled wetland soundscapes in urbanized and rural areas in northeastern Ohio, and used Raven software to analyze the data. Above the water line, average sound power was 38.9db–73.9db, which was similar to below the water line (48.6db–78.5db). Frequencies in the band 0–5 kHz had the highest overall power both above and below the water. One of the most urbanized sites had above/below readings as high as 83.9/79.3 dB. In comparison, one of the most rural sites had readings as low as 47.6/66.8 dB. At both urbanized and rural sites, the 0–5 kHz band had the highest overall power. I further tested if wetland invertebrates could be impacted by anthropogenic sounds. I found that Procambarus acutus crayfish produced audible clicks (frequency range 6 kHz–45 kHz, average power 69–73.5 dB). Ongoing laboratory research is testing if motorboat noise affects P. acutus behavior and sound production.

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.