Pediatric burden and seasonality of Human Metapneumovirus over five
years in Managua, Nicaragua.
Background Human Metapneumovirus (hMPV) is an important cause of
pediatric respiratory infection. We leveraged the Nicaraguan Pediatric
Influenza Cohort Study (NPICS) to assess the burden and seasonality of
symptomatic hMPV infection in children. Methods NPICS is an ongoing
prospective study of children in Managua, Nicaragua. We assessed
children for hMPV infection via RT-PCR. We used classical additive
decomposition analysis to assess the temporal trends and Generalized
Growth Models (GGMs) were used to estimate effective reproduction
numbers. Results From 2011-2016 there were 564 hMPV symptomatic
infections yielding an incidence rate of 5.74 cases per 100 person-years
(95% CI 5.3, 6.2). Children experienced 3,509 Acute Lower Respiratory
Infections (ALRIs), of which 160 (4.6%) were associated with hMPV
infection. Children under the age of one had 55% of all symptomatic
hMPV infections (62/112) develop into hMPV-associated ALRIs and were
five times as likely as children over one to have an hMPV-associated
ALRI (Rate Ratio 5.5 95% CI 4.1, 7.4 p <0.001). Additionally,
symptomatic reinfection with hMPV was common. In total, 87 (15%) of all
observed symptomatic infections were reinfections. The seasonality of
symptomatic hMPV outbreaks varied considerably. From 2011-2016, four
epidemic periods were observed, following a biennial seasonal pattern.
The mean ascending phase of the epidemic periods were 7.7 weeks, with an
overall mean estimated reproductive number of 1.2 (95% CI 1.1, 1.4).
Conclusions Symptomatic hMPV infection was associated with substantial
burden among children in the first year of life. Timing and frequency of
symptomatic hMPV incidence followed biennial patterns.