The risk for intussusception after monovalent human rotavirus vaccine administration may not be higher than the background risk for intussusception in 7 lower-income sub-Saharan African countries, according to a recently published study in The New England Journal of Medicine.
The RotaShield® vaccine (Wyeth-Lederle Laboratories) was previously associated with intussusception and consequently withdrawn from use. The World Health Organization (WHO) recommended that intussusception be carefully monitored during clinical trials of newer rotavirus vaccines, including the monovalent Rotarix vaccine (RV1; GlaxoSmithKline) and the pentavalent RotaTeq® vaccine (RV5; Merck).
Although pre-licensure RV1 and RV5 clinical trials did not find an intussusception association, post-marketing surveillance did within several high- and middle-income countries after the first week of receiving the first dose of vaccine.
In 2017, the rotavirus vaccine was introduced into 32 sub-Saharan African countries, where more than half of all rotavirus-responsible deaths occur. Unfortunately, large-scale safety assessment data of rotavirus vaccines is lacking in low-income countries.
Therefore, this study assessed whether there was an association between RV1 vaccination and intussusception in 7 low- and low-middle income sub-Saharan African countries.
Using active surveillance, 717 infants from 7 countries (Ethiopia, Ghana, Kenya, Malawi, Tanzania, Zambia, and Zimbabwe) who had intussusception were included. Rotavirus vaccination status was confirmed by review of vaccine card or clinic records.
The risk of intussusception within 1 to 7 days and 8 to 21 days after vaccination in infants age 28 to 245 days was assessed by means of the self-controlled-case-series method.
After the first dose, 1 case occurred in the 1 to 7-day period after vaccination and 6 cases occurred in the 8 to 21-day period. After the second dose, 5 cases occurred in the 1 to 7 day-period after vaccination and 16 cases occurred in the 8 to 21-day period after vaccination.
The risk for intussusception in the 1 to 7-day period after dose 1 was not higher than the background risk for intussusception (relative incidence [ie, the incidence during the risk window vs all other times], 0.25).
In addition, findings were similar for the 1 to 7-day period after dose 2 (relative incidence, 0.76). Furthermore, the intussusception risk in the 8 to 21-day period or 1 to 21-day period after either dose 1 or dose 2 was not found to be higher than the background risk.
These findings contrast with previous studies in high- and middle-income countries, where an association with intussusception was found. Other factors may play a role in the risk of intussusception that differ between low-income African countries and high- and middle-income countries and might partially account for the differences in the risk for intussusception after RV1 vaccination.
Overall, the study investigators concluded that, “the risk of intussusception after administration of monovalent human rotavirus vaccine was not higher than the background risk of intussusception in 7 lower-income sub-Saharan African countries.”
Tate JE, Mwenda JM, Armah G, et al. Evaluation of intussusception after monovalent rotavirus vaccination in Africa. New Engl J Med. 2018; 378;16. doi:10.1056/NEJMoa1713909