Determining effectiveness of rotavirus vaccine by immunochromatography and reverse transcriptase polymerase chain reaction: A comparison

Abstract Introduction Because of the large animal reservoirs and reassortment capacity of rotaviruses (RVs) that pose the possibilities of waning the effectiveness of RV-vaccines, it remains essential to monitor vaccine effectiveness (VE) regularly. Although reverse transcription polymerase chain reaction (RT-PCR) remains sensitive for RV detection, physicians, especially in Japan, frequently use immunochromatography (IC)-based kits for RV diagnosis. Recently, IC is being used to calculate VE also. Herein, we investigated the validity of VEs determined by IC compared to that by RT-PCR during an outbreak in Shizuoka Prefecture, Japan. Methods RVs in the stool or rectal swabs from children with acute gastroenteritis (AGE) were tested first by IC in the clinic and then by RT-PCR in the laboratory. A test-negative study design was used to examine VE. Results Although the specificity of IC assay revealed 100%, its sensitivity remained weaker (67%) than that of RT-PCR that increased up to 88% depending on disease severity. VE assessed by IC remained stronger than that by RT-PCR: 79% (95% CI: 39–93%) by IC, and 58% (95% CI: −20% to 90%) by RT-PCR. However, VEs by IC and RT-PCR appeared almost similar in higher disease severity: 81.5% (95% CI: 40–94%) by IC and 72% (95% CI: 7–92%) by RT-PCR at severity ≥7, while 97.5% (95% CI: 77–99.7%) by IC and 92% (95% CI: 58–98%) by RT-PCR at severity ≥11. We showed that RV-vaccinated children had 80% [OR = 0.192 (95% CI: 0.052–0.709) less chance to be detected by IC. Conclusion Although the sensitivity and specificity of IC differ by brand type, generally, IC is not as sensitive as RT-PCR. Despite the VEs remain higher by IC, it looks comparable with that of RT-PCR in severe cases implying that VEs evaluated by IC against severe illness remain useful for VE-monitoring.