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The duration and nature of immunity generated in response to SARS-CoV-2 infection is unknown. Many public health responses and modeled scenarios for COVID-19 outbreaks caused by SARSCoV-2 assume that infection results in an immune response that protects individuals from future infections or illness for some amount of time. The timescale of protection is a critical determinant of the future impact of the pathogen. The presence or absence of protective immunity due to infection or vaccination (when available) will affect future transmission and illness severity. The dynamics of immunity and nature of protection are relevant to discussions surrounding therapeutic use of convalescent sera as well as efforts to identify individuals with protective immunity. Here, we review the scientific literature on antibody immunity to coronaviruses, including SARS-CoV-2 as well as the related SARS-CoV-1, MERS-CoV and human endemic coronaviruses (HCoVs). We reviewed 1281 abstracts and identified 322 manuscripts relevant to 5 areas of focus: 1) antibody kinetics, 2) correlates of protection, 3) immunopathogenesis, 4) antigenic diversity and cross-reactivity, and 5) population seroprevalence. While studies of SARS-CoV-2 are necessary to determine immune responses to it, evidence from other coronaviruses can provide clues and guide future research.

Many public health responses and modeled scenarios for COVID-19 outbreaks caused by SARS-CoV-2 assume that infection results in an immune response that protects individuals from future infections or illness for some amount of time. The presence or absence of protective immunity due to infection or vaccination (when available) will affect future transmission and illness severity. Here, we review the scientific literature on antibody immunity to coronaviruses, including SARS-CoV-2 as well as the related SARS-CoV, MERS-CoV and endemic human coronaviruses (HCoVs). We reviewed 2,452 abstracts and identified 491 manuscripts relevant to 5 areas of focus: 1) antibody kinetics, 2) correlates of protection, 3) immunopathogenesis, 4) antigenic diversity and cross-reactivity, and 5) population seroprevalence. While further studies of SARS-CoV-2 are necessary to determine immune responses, evidence from other coronaviruses can provide clues and guide future research.

Background: The association of hemagglutination inhibition (HAI) antibodies with protection from influenza among healthcare personnel (HCP) with occupational exposure to influenza viruses has not been well-described.Methods: The Respiratory Protection Effectiveness Clinical Trial was a cluster-randomized, multisite study that compared medical masks to N95 respirators in preventing viral respiratory infections among HCP in outpatient healthcare settings for 5180 participant-seasons. Serum HAI antibody titers before each influenza season and influenza virus infection confirmed by polymerase chain reaction were studied over 4 study years.Results: In univariate models, the risk of influenza A(H3N2) and B virus infections was associated with HAI titers to each virus, study year, and site. HAI titers were strongly associated with vaccination. Within multivariate models, each log base 2 increase in titer was associated with 15%, 26% and 33%-35% reductions in the hazard of influenza A(H3N2), A(H1N1), and B infections, respectively. Best models included preseason antibody titers and study year, but not other variables.Conclusions: HAI titers were associated with protection from influenza among HCP with routine exposure to patients with respiratory illness and influenza season contributed to risk. HCP can be reassured about receiving influenza vaccination to stimulate immunity. [ABSTRACT FROM AUTHOR]

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents a large risk to healthcare personnel (HCP). Quantifying the risk of coronavirus infection associated with workplace activities is an urgent need. Methods We assessed the association of worker characteristics, occupational roles and behaviors, and participation in procedures with the risk of endemic coronavirus infection among HCP who participated in the Respiratory Protection Effectiveness Clinical Trial (ResPECT), a cluster randomized trial to assess personal protective equipment to prevent respiratory infections and illness conducted from 2011 to 2016. Results Among 4689 HCP seasons, we detected coronavirus infection in 387 (8%). HCP who participated in an aerosol-generating procedure (AGP) at least once during the viral respiratory season were 105% (95% confidence interval, 21%–240%) more likely to be diagnosed with a laboratory-confirmed coronavirus infection. Younger individuals, those who saw pediatric patients, and those with household members <5 years of age were at increased risk of coronavirus infection. Conclusions Our analysis suggests that the risk of HCP becoming infected with an endemic coronavirus increases approximately 2-fold with exposures to AGPs. Our findings may be relevant to the coronavirus disease 2019 (COVID-19) pandemic; however, SARS-CoV-2, the virus that causes COVID-19, may differ from endemic coronaviruses in important ways. Clinical Trials Registration NCT01249625. [ABSTRACT FROM AUTHOR]

Introduction: Current guidelines for the outpatient treatment of severe acute malnutrition (SAM) recommend the provision of routine medications to all children at admission and prescribed medications as clinically indicated thereafter. The objective of this study was to describe the amount and purpose of medications prescribed during outpatient SAM treatment and explore the effect of routine antibiotics at admission on subsequent medication prescription., Methods: Medications prescribed during outpatient treatment were described by medication category, time from admission, and diagnoses among children with SAM in a placebo-controlled, double-blind trial of 7-day amoxicillin use. Total medications were compared by parent trial intervention arm (amoxicillin vs placebo) and differences assessed using Χ 2 and two-sample t-tests., Results: Of the 2399 children enrolled, 74.6% of children received ≥1 prescribed medication during outpatient treatment. Antipyretics/analgesics (44.1% of children), antimalarials (56.6%) and antibiotics (30.0%) were prescribed most frequently. Children who received placebo in the parent trial received fewer total medications (mean difference: -0.80, 95% CI: -0.96 to -0.65) and oral antibiotics (mean difference: -0.96, 95% CI: -0.99 to -0.92) during treatment compared with children who received routine amoxicillin., Conclusions: We found high rates of medication prescription during outpatient treatment for SAM, but fewer total medications and oral antibiotics prescribed to children receiving placebo in the parent trial. Our findings underscore the role of outpatient treatment programmes as an important source of medicine prescription and suggest that provision of antibiotics on a clinically indicated basis for outpatient SAM cases may be a strategy to support prudent antibiotic use in certain settings., Trial Registration Number: ClinicalTrials.gov Registry (NCT01613547; https://clinicaltrials.gov/ct2/show/NCT01613547)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)