vIRus In Summer

Background: Human metapneumovirus (HMPV) is a virus belonging to the Paramyxoviridae family and has been known since 2001. Symptoms may include wheezing, increased breath effort, and a severe cough. The virus is a known causative agent of pneumonia in both children and the elderly, immunocompromised and it can cause exacerbations in patients with COPD. Studies by our group showed that it can be associated with significant mortality and that the clinical picture in adults is very similar to COVID-19. However, there is an important difference with COVID-19: while COVID-19 shows itself as an erratic pandemic with high peaks and deep drops in incidence, HMPV continued to behave as a purely seasonal virus until 2020 with an annual high incidence in the spring and complete decline in the summer. However, in 2021, after a year of COVID-19 measures, there is evidence that HMPV incidence shifted from spring, in which it was now barely detected, to summer.
Purpose: Through this retrospective subject study, we want to gain insight into suspected shifts in incidence of HMPV, both in children and adults. We also want to gain insight into whether it is 1 cluster of introduction or whether there are multiple genotypes circulating. Finally, we want to compare clinical outcomes of adult patients in June/July 2021 with the previously collected historical cohort, as well as differences between children and adults in June/July 2021.
Methods: This retrospective cohort analysis will look at the incidence of HMPV infection in patients who were admitted to Zuyderland Medical Center between 1/1/16 and 1/8/21. Both children and adults will be included for this purpose.
The cohort of patients admitted between 1/6/21 and 1/8/21 will be studied in more detail. In these cases genotyping of HMPV will be performed and clinical outcomes of patients will be collected. Genotyping will be performed in close collaboration with the Erasmus University. The main clinical outcomes that will be observed are: mortality, ICU admission and length of hospital stay.

It is expected to see a shift with respect to the prevalence of HMPV infection compared to previous cohorts.

T0= hospital admission T1= 30 days after hospital discharge