Monitoring of rotavirus vaccination in Morocco: establishing the baseline burden of rotavirus disease.

BACKGROUND

Rotavirus is a leading cause of childhood morbidity and mortality worldwide. Clinical trials for two rotavirus vaccines recommended by the WHO for global use since 2009 have successfully demonstrated the safety and efficacy of these vaccines in a wide range of countries. To control the burden of severe and fatal diarrheal disease, the Ministry of Health of Morocco introduced the single strain rotavirus vaccine into their national immunization program in 2010.

METHODS

We employed a standard WHO case definition to identify children under 5 hospitalized with AGE at four hospitals from June 2006 to May 2010 to establish baseline burden of rotavirus disease before introduction of vaccine. Stool samples were collected and tested for rotavirus using a standard enzyme immunoassay.

RESULTS

Overall, 40% (741 of 1841) of the children hospitalized with AGE tested positive for rotavirus, making it the single most common cause of severe gastroenteritis among children in Morocco. Applying this prevalence to the estimates of diarrheal hospitalizations and deaths in Morocco, we estimate that rotavirus annually causes 19,646 hospitalizations and 1604 deaths in children under 5 years of age.

DISCUSSION

On the basis of these surveillance data, we estimate that 1 in 389 Moroccan children died and 1 in 32 was hospitalized due to rotavirus before their fifth birthday. A considerable proportion of these deaths and hospitalizations should be preventable through vaccination, and the 4 years of stable prevaccine surveillance in Morocco will be a tremendously useful platform for assessing potential changes in the epidemiology of rotavirus disease and measuring impact of the new rotavirus vaccine program in Morocco.