Clinical characteristics, predictors, and performance of case definition—Interim results from the WHO global respiratory syncytial virus surveillance pilot

Siddhivinayak Hirve, Nigel Crawford, Rakhee Palekar, Wenqing Zhang, on behalf of the WHO RSV surveillance Group


Since 2016, the WHO have been conducting a pilot study aimed at leveraging the capacity of the currently existing Global Influenza Surveillance and Response System (GISRS) to survey the global yearly epidemics of RSV and their impact on public health. Surveillence was conducted in 14 sites, and at least 1000 patients were tested annually for RSV (250 patients in each of the four age groups—<6 months, 6 months to <5 years, 5 to <65 years, and 65 years and more).
Different recruitment criteria were used for each group, for example patients recruited from outpatient clinics only required a runny nose, cough, soreness or shortness of breath, whereas inpatients required acute onset cough or shortness of breath. Sepsis and Apnea were also enrollment criteria for children below the age of 6 months.
21,221 patients were tested for RSV, of which 73% were inpatients. The majority of patients were below 5 years of age, and the age distributions differed from country to country. The percentage of patients positive for RSV was 37% in children <6 months and 25% between children aged 6 months to 2 years. Patients with fever were less likely to be RSV positive compared to those without fever . For infants <6 months, 29% of RSV ARI cases did not have fever

The results of this pilot study bring into question the utility of current case definitions for RSV infections in surveillence. Currently fever is a requirement to be considered a case, and this may create difficulties or biases by reducing sensitivity in some populations with a high burden, such as children <2 years of age. It was also observed that usage of the same facilities as are used for influenza surveillence for parallel RSV surveillence did not decrease the quality of influenza surveillence. Integration of RSV testing into the GISRS could drastically increase the body of epidemiological data for RSV, and aid in the prediction of seasonality and severity of seasons regionally.

Full article on PubMed.