Rotavirus burden decreases, epidemiology changes after 2006 vaccination implementation

SAN DIEGO — Data presented here at IDWeek 2015 suggest that population vaccination policies implemented in 2006 reduced the burden of rotavirus and altered seasonal epidemiology of the disease.

“In the pre-vaccine period there were about 2.7 million episodes of acute gastroenteritis with between 200,000 and 270,000 ED visits, over 400,000 outpatient visits, 55,000 to 70,000 hospitalizations and 20 to 60 deaths,” Negar Aliabadi, MD, of the CDC’s National Center for Immunization and Respiratory Diseases, said during a presentation. “In 2006, a vaccine became available and the ACIP … recommended routine use in all U.S. infants.”

Negar Aliabadi

To examine the impact of this recommendation, Aliabadi and colleagues analyzed data from the National Respiratory and Enteric Virus Surveillance System (NREVSS), a U.S. passive laboratory system collecting weekly testing information. Cumulative and positive specimen data were collected from continuously reporting laboratories from January 2000 to March 31, 2015, and median values for time periods before and after vaccination implementation were compared. In addition to incidence, characteristics of yearly rotavirus seasons including peak, duration and onset were examined.

The researchers saw an overall decline in positive rotavirus tests in the years after implementation. Compared with the 2000 to 2006 baseline period, rotavirus reduction ranged from 57.8% to 89.9% for each subsequent year. Rotavirus season duration dropped after vaccination, began later and peaked at lower levels of activity.

In addition, Aliabadi said an interesting, albeit predicted, finding was the development of a biennial incidence pattern. Years subsequent to the implementation of vaccination alternated between lower and greater rotavirus activity, a pattern that she said could be the result of unvaccinated children having not been exposed to wild rotavirus during years of greater protection.

“These findings affirm the large public health impact of routine rotavirus vaccination in the U.S.,” Aliabadi concluded. – by Dave Muoio

Reference:

Aliabadi N, et al. Abstract 747. Presented at: IDWeek; Oct. 7-11, 2015; San Diego.

Disclosure: The researchers report no relevant financial disclosures.