Surveillance data confirm multiyear predictions of rotavirus dynamics in New York City

Abstract

Prediction skill is a key test of models for epidemic dynamics. However, future validation of models against out-of-sample data is rare, partly because of a lack of timely surveillance data. We address this gap by analyzing the response of rotavirus dynamics to infant vaccination. Syndromic surveillance of emergency department visits for diarrhea in New York City reveals a marked decline in diarrheal incidence among infants and young children, in line with data on rotavirus-coded hospitalizations and laboratory-confirmed cases, and a shift from annual to biennial epidemics increasingly affecting older children and adults. A published mechanistic model qualitatively predicted these patterns more than 2 years in advance. Future efforts to increase vaccination coverage may disrupt these patterns and lead to further declines in the incidence of rotavirus-attributable gastroenteritis.

Fig. 1. Vaccination registry, rotavirus hospitalization, and laboratory-reported case data in New York City, January 2002 through December 2016.

(A) Monthly counts of children age 8 months to <2 years receiving the complete series of rotavirus vaccine as recorded in the Citywide Immunization Registry (CIR) are shown in green. (B) Monthly counts of rotavirus-coded inpatient hospitalizations from January 2002 through December 2016 are shown in blue, and (C) notifiable laboratory-reported cases from February 2008 through December 2016 are shown in yellow. Epidemic rotavirus periods are shaded in gray and are identified as months, in which both the number of rotavirus-coded hospitalizations and laboratory-reported cases met or exceeded their respective upper quartile of cases observed over the entire period of available data.

Fig. 2. Weekly diarrheal syndrome ED visit proportions by age group, January 2002 through June 2016 in New York City.

Weekly percentage of diarrheal syndrome ED visits are shown (red lines) with periodic regression baseline expected percentages (gray lines) with 95% threshold levels (dashed lines) by age group: (A) <2, (B) 2 to 4, (C) 5 to 12, and (D) ≥13 years. Epidemic rotavirus periods are shaded in gray, as identified on the basis of rotavirus-coded hospitalization and laboratory-reported data.

Fig. 3. Predicted incidence of severe RVGE in New York, 2002–2024.

Dynamic model predictions are based on a previously described mathematical model fit to monthly hospitalization data from New York State (1993–2004), which was simulated to predict the impact of vaccination through 2024. Model predictions for the monthly number of moderate-to-severe RVGE cases in individuals (A) <2, (B) 2 to 4, and (C) ≥5 years old are plotted in blue, while the observed laboratory-reported cases are plotted in yellow. (D) Vaccine coverage in the model is based on estimates of rotavirus vaccine coverage with at least one (blue) and the full series (green) from the CIR. Coverage with a full course of rotavirus vaccine was increased to the current vaccine coverage with the DTaP vaccine beginning in January 2018 (black dashed lines) or 2019 (red dashed lines). We assumed that the relative efficacy of an incomplete vaccine course was 88% (see the Supplementary Materials).