ABSTRACT
Background Evidence suggests that early, robust type 1 interferon responses to SARS-CoV-2 are critical determinants for COVID-19 disease outcomes, accelerating viral clearance and limiting viral shedding. Accordingly, we undertook a ring prophylaxis study to determine whether pegylated IFN{beta}-1 could reduce SARS-CoV-2 household transmission. Methods A household cluster randomized controlled study of IFN{beta}-1 administered to non-hospitalized, symptomatic COVID-19 index cases and treatment-eligible household contacts aged 18-70 years compared to standard care, was conducted. Following randomization participants received IFN{beta}-1 on days 1, 6, and 11 or standard care. Viral shedding was determined by sequential salivary polymerase chain reaction measurements until day 29 in both study arms. A post-hoc at risk population was defined as households where the index case was positive at the start of the study and there was at least one treatment eligible contact in a household who tested negative for SARS-CoV-2. Frequentist and Bayesian analyses were undertaken to determine the effects of treatment on (i) reducing viral shedding in index cases and (ii) reducing viral transmission to post-exposure household contacts. Results In total, 1172 participants in 341 households underwent randomization, with 607 assigned to receive IFN{beta}-1 and 565 to standard care. Based on intention to treat and per protocol analyses, IFN{beta}-1 treatment was ineffective. However, in the at risk population, the relative risk of infection was reduced by 23% in treated individuals and that there was a 95% probability that IFN{beta}-1 reduced household transmission. Conclusion Ring prophylaxis with IFN{beta}-1 reduces the probability of SARS-CoV-2 transmission within a household.
Subject(s)
COVID-19ABSTRACT
BackgroundMultiple vaccines against SARS-CoV-2 have been evaluated in clinical trials, but very few include the pediatric population. The inactivated vaccine CoronaVac(R) has shown to be safe and immunogenic in a phase 1/2 clinical trial in a pediatric cohort in China. This study is an interim safety and immunogenicity report of a phase 3 clinical trial for CoronaVac(R) in healthy children and adolescents in Chile. MethodsParticipants aged 3 to 17 years old received two doses of CoronaVac(R) in a four-week interval. Local and systemic adverse reactions were registered in 699 participants that received the first dose and 381 that received the second dose until December 31st, 2021. Whole blood samples were collected from 148 participants for humoral and cellular immunity analyses. ResultsThe primary adverse reaction reported after the first and second dose was pain at the injection site. The adverse reactions observed were primarily mild and local, and no severe adverse events were reported. Four weeks after the second dose, a significant increase in the levels of total and neutralizing antibodies was observed. Increased activation of specific CD4+ T cells was also observed four weeks after the second dose. Although antibodies induced by vaccination neutralize variants Delta and Omicron, titers were lower than the D614G variant. Importantly, comparable T cell responses were detected against these variants of concern. ConclusionsCoronaVac(R) is safe and immunogenic in subjects aged 3-17 years old and is thus likely to confer protection against infection caused by SARS-CoV-2 variants in this target population.