Respiratory viruses (RV) are a leading cause of infection-related morbidity and mortality for patients undergoing treatment for cancer. This analysis compared duration of RV shedding as detected by culture and PCR among patients in a high-risk oncology setting (adult patients with haematological malignancy and/or stem cell transplant and all paediatric oncology patients) and determined risk factors for extended shedding. RV infections due to influenza virus, parainfluenza virus (PIV), human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) from two study periods—January 2009–September 2011 (culture-based testing) and September 2011–April 2013 (PCR-based testing)—were reviewed retrospectively. Data were collected from patients in whom re-testing for viral clearance was carried out within 5–30 days after the most recent test. During the study period 456 patients were diagnosed with RV infection, 265 by PCR and 191 by culture. The median range for duration of shedding (days) by culture and PCR, respectively, were as follows—influenza virus: 13 days (5–38 days) versus 14 days (5–58 days), p 0.5; RSV: 11 days (5–35 days) versus 16 days (5–50 days), p 0.001; PIV: 9 days (5–41 days) versus 17 days (5–45 days), p ≤0.0001; HMPV 10.5 days (5–29 days) versus 14 days (5–42 days), p 0.2. In multivariable analysis, age and underlying disease or transplant were not independently associated with extended shedding regardless of testing method. In high-risk oncology settings for respiratory illness due to RSV and PIV, the virus is detectable by PCR for a longer period of time than by culture and extended shedding is observed.

Background: Three SARS-CoV-2 vaccines, two based on mRNA, BNT162b2 and mRNA-1273, and one based on an adenovirus platform, Ad26.COV2.S, received emergency use authorization by the U.S. Food and Drug Administration in 2020/2021. These vaccines displayed clinical efficacy in initial studies against confirmed COVID-19 of 95.0%, 94.1%, and 66.9%, respectively. Methods: Individuals receiving one of these vaccines were invited to participate in a prospective longitudinal comparative study of immune responses elicited by the three vaccines. In this observational cohort study, humoral responses were evaluated using a SARS-CoV-2 receptor-binding domain (RBD) ELISA and a SARS-CoV-2 virus neutralization assay at 21-32 days and again at 47-64 days following each initial vaccination. Results: The two mRNA-based platforms elicited similar RBD ELISA responses, but significantly higher neutralizing antibody responses were achieved by mRNA-1273. The adenovirus-based vaccine elicited significantly lower RBD ELISA and SARS-CoV-2 virus neutralization activity. IFN-gamma ELISPOT assays were conducted with peripheral blood mononuclear cells obtained 47-64 days after each initial vaccination. The mRNA-1273 vaccine elicited significantly higher spike glycoprotein-specific T cell responses than either the BNT162b2 or the Ad26.COV2.S vaccines. Conclusions: These findings are consistent with published efficacy data for the three vaccines and support the use of neutralizing antibody titers as a correlate of protection against symptomatic COVID-19.

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SARS-CoV-2 vaccines BNT162b2, mRNA-1273, and Ad26.COV2.S received emergency use authorization by the U.S. Food and Drug Administration in 2020/2021. Individuals being vaccinated were invited to participate in a prospective longitudinal comparative study of immune responses elicited by the three vaccines. In this observational cohort study, immune responses were evaluated using a SARS-CoV-2 spike protein receptor-binding domain ELISA, SARS-CoV-2 virus neutralization assays and an IFN- γ ELISPOT assay at various times over six months following initial vaccination. mRNA-based vaccines elicited higher magnitude humoral responses than Ad26.COV2.S; mRNA-1273 elicited the most durable humoral response, and all humoral responses waned over time. Neutralizing antibodies against the Delta variant were of lower magnitude than the wild-type strain for all three vaccines. mRNA-1273 initially elicited the greatest magnitude of T cell response, but this declined by 6 months. Declining immunity over time supports the use of booster dosing, especially in the setting of emerging variants.