Reduction in Severity of All-Cause Gastroenteritis Requiring Hospitalisation in Children Vaccinated against Rotavirus in Malawi

Abstract

Rotavirus is the major cause of severe gastroenteritis in children aged <5 years. Introduction of the G1P[8] Rotarix® rotavirus vaccine in Malawi in 2012 has reduced rotavirus-associated hospitalisations and diarrhoeal mortality. However, the impact of rotavirus vaccine on the severity of gastroenteritis presented in children requiring hospitalisation remains unknown. We conducted a hospital-based surveillance study to assess the impact of Rotarix® vaccination on the severity of gastroenteritis presented by Malawian children. Stool samples were collected from children aged <5 years who required hospitalisation with acute gastroenteritis from December 2011 to October 2019. Gastroenteritis severity was determined using Ruuska and Vesikari scores. Rotavirus was detected using enzyme immunoassay. Rotavirus genotypes were determined using nested RT-PCR. Associations between Rotarix® vaccination and gastroenteritis severity were investigated using adjusted linear regression. In total, 3159 children were enrolled. After adjusting for mid-upper arm circumference (MUAC), age, gender and receipt of other vaccines, all-cause gastroenteritis severity scores were 2.21 units lower (p < 0.001) among Rotarix®-vaccinated (n = 2224) compared to Rotarix®-unvaccinated children (n = 935). The reduction in severity score was observed against every rotavirus genotype, although the magnitude was smaller among those infected with G12P[6] compared to the remaining genotypes (p = 0.011). Each one-year increment in age was associated with a decrease of 0.43 severity score (p < 0.001). Our findings provide additional evidence on the impact of Rotarix® in Malawi, lending further support to Malawi’s Rotarix® programme.

Impact of rotavirus vaccine introduction in Abidjan, Côte d’Ivoire

“…We also observed a decrease in the severity of AGE, although this decrease was not significant among rotavirus-positive cases. Decreased severity of rotavirus and AGE cases is consistent with previous research from Malawi, 13 and may be a mechanism for the decreases in AGE mortality often observed following rotavirus vaccine introduction. 4 …”

Impact of rotavirus vaccination in Malawi from 2012 to 2022 compared to model predictions before, during, and after the COVID-19 pandemic

“…Nevertheless, other studies have found that the severity of hospitalized RVGE cases has decreased since the introduction of RV1 [20], and infant mortality from all-cause diarrhea has also declined [25]. Thus, there may be additional benefits to vaccine introduction that have not been quantified in this analysis.…”

Leveraging Beneficial Off-Target Effects of Live-Attenuated Rotavirus Vaccines

“…However, there are important questions that remain to be addressed in order to utilise this intrinsic feature of vaccines to inform vaccine design. To date, limited studies have analysed the putative off-target beneficial effects of live-attenuated rotavirus vaccines either from an epidemiological or mechanistic point of view [ 90 , 91 , 92 ]. Moreover, it is not clear whether live-attenuated rotavirus vaccines incorporated into immunisation programmes would influence the performance of other vaccines known to induce off-target effects, such as BCG.…”