Pre-admission RT-qPCR based RSV screening reduces nosocomial RSV infections during epidemic outbreaks

Background. The burden of nosocomial respiratory syncytial virus (RSV) infections makes preventing strategies a primary concern. During an unexpected RSV epidemic, a pre-admission real-time polymerase-chain-reaction (RT-PCR) based screening program was introduced in our tertiary pediatric hospital, to reduce nosocomial RSV infections. Methods. In the pre-screening period all children received a pre-admission SARS-CoV-2 test, while after November 23 rd , 2021, a combined SARS-CoV-2 and RSV test was universally performed. All children diagnosed with RSV infection during hospitalization were retrospectively evaluated to investigate the rate of nosocomial RSV infections in the two periods. An RSV infection was defined as nosocomial when occurred >48h from admission and a previous RSV-negative test was available. Nasal swabs performed at admission for SARS-CoV-2 and stored for surveillance purposes were retested for RSV to evaluate the presence of the virus before hospitalization, whenever necessary. Results. We included 332 children aged 0-14y with RSV infection, 151 before and 181 after the protocol introduction. No differences in terms of mean age, intensive care unit admission, and coinfections were found between the two groups. Overall, we identified 12 nosocomial RSV infections, 10 in the pre-screening group and two after. The incidence of nosocomial RSV infections was significantly reduced from 6.6% to 1.1% (p=0.014, Fisher’s exact test) following the introduction of the screening protocol. Conclusions. Pre-admission RT-PCR based screening is effective in reducing the incidence of nosocomial RSV during epidemic outbreaks. RT-PCR technologies might allow to rapidly introduce the same approach for other viral agents, depending on the epidemiological need.