Vaccination after infection enhances antibody responses against variants
Prior SARS-CoV-2 infection rescues B and T cell responses to variants after first vaccine dose
We analyzed T and B cell responses after first dose vaccination with the Pfizer/BioNTech mRNA vaccine BNT162b2 in healthcare workers (HCW) followed longitudinally, with or without prior Wuhan-Hu-1 SARS-CoV-2 infection. After one dose, individuals with prior infection showed enhanced T cell immunity, antibody secreting memory B cell response to spike and neutralizing antibodies effective against B.1.1.7 and B.1.351. By comparison, HCW receiving one vaccine dose without prior infection showed reduced immunity against variants. Single dose vaccination with BNT162b2 in the context of prior infection with a heterologous variant substantially enhances neutralizing antibody responses against variants.
SARS-CoV-2 transmission in a Georgia school district — United States, December 2020–January 2021
During December 1, 2020–January 22, 2021, SARS-CoV-2–infected index cases and their close contacts in schools were identified by school and public health officials. We identified 86 index cases and 1,119 contacts, 688 (63.1%) of whom received testing. Fifty-nine (8.7%) of 679 contacts tested positive; 15 (17.4%) of 86 index cases resulted in ≥2 positive contacts. Among 55 persons testing positive with available symptom data, 31 (56.4%) were asymptomatic. Highest SAR were in indoor, high-contact sports settings (23.8%, 95% confidence interval [CI] 12.7, 33.3), staff meetings/lunches (18.2%, CI 4.5–31.8), and elementary school classrooms (9.5%, CI 6.5–12.5). SAR was higher for staff (13.1%, CI 9.0–17.2) versus student index cases (5.8%, CI 3.6–8.0) and for symptomatic (10.9%, CI 8.1–13.9) versus asymptomatic index cases (3.0%, CI 1.0–5.5). Indoor sports may pose a risk to the safe operation of in-person learning. Because many positive contacts were asymptomatic, contact tracing should be paired with testing, regardless of symptoms.
Implementation of preventive measures to prevent COVID-19: a national study of English primary schools in summer 2020
We examined the feasibility of implementing preventive measures to prevent SARS-CoV-2 transmission across 105 English primary schools in summer 2020 via a survey and interviews with headteachers. High rates of implementation of most recommended measures were noted with the exception of requiring 2 m distance for students, fitting hand sanitizers in classrooms and introducing one-way systems in school corridors. Measures such as regular handwashing and stopping assemblies were considered easy to implement. Majorly challenging measures included distancing between individuals (for students: 51%, N = 99; for staff: 34%; N = 98; for parents: 26%, N = 100), spacing out desks (34%, N = 99), keeping same staff assigned to each student group (33%, N = 97) and staggering break times (25%, N = 99). Rapid implementation was facilitated by staff commitment and communication among stakeholders, but hampered by limitations with guidance received, physical environments, resources, parental adherence and balancing preventive measures with learning.
Inactivation of SARS-CoV-2 in chlorinated swimming pool water
[Preprint.] Swimming pools have reopened in the UK as of April 12th, but the effect of swimming pool water on inactivation of SARS-CoV-2 has not yet been directly demonstrated. Here we demonstrate that water which adheres to UK swimming pool guidelines is sufficient to reduce SARS-CoV-2 infectious titre by at least 3 orders of magnitude.
Immunity after SARS-CoV-2 infections
T cell responses probably play important roles in the control of SARS-CoV-2 infection, but they have been relatively understudied. Data now suggest that the majority of infected individuals develop robust and long-lasting T cell immunity, which has implications for the durability of immunity and future vaccine approaches.