Trends in Laboratory Rotavirus Detection: 2003 to 2014

Area of Science:

• Virology
• Immunology
• Public Health

Background:

• Rotavirus is a leading cause of severe diarrheal disease in infants and young children globally.
• Rotavirus vaccination has been implemented to reduce disease burden, but its impact on surveillance data and disease seasonality requires ongoing assessment.

Purpose of the Study:

• To evaluate the national and state-level impact of rotavirus vaccination on rotavirus antigen detection.
• To examine evidence of herd immunity and waning immunity with aging in vaccinated and unvaccinated cohorts.
• To propose a novel method for estimating rotavirus season length.

Main Methods:

• Analysis of 11 years of rotavirus testing data (n=276,342) from a national clinical reference laboratory (September 2003 - August 2014).
• Utilized enzyme immunoassay for rotavirus antigen detection in stool specimens.
• Compared rotavirus positivity rates and seasonality before and after vaccine licensure.

Main Results:

• A significant national reduction in rotavirus detection (82.4% decrease in positive results, 73.3% decrease in positivity rate) was observed post-vaccination.
• Declining positivity rates in unvaccinated children suggested herd immunity.
• Higher positivity rates in older vaccinated children indicated potential waning immunity.
• Rotavirus seasons were observed to be longer in the post-vaccine period.

Conclusions:

• Rotavirus vaccination has led to a substantial decrease in national rotavirus detection, supporting its effectiveness and the presence of herd immunity.
• Evidence suggests that vaccine effectiveness may wane with age.
• The duration of rotavirus seasons appears to have increased following widespread vaccination.