Impact of rotavirus vaccine on diarrheal hospitalization and outpatient consultations in the Philippines: First evidence from a middle-income Asian country.

Background: Monovalent rotavirus (RV) vaccine was introduced in the Philippines in a phased manner beginning in 2012. To assess the impact of RV vaccine, we conducted a retrospective review of diarrheal admissions in two hospitals.

Methods: Records of physician-diagnosed diarrheal admissions were reviewed in D.O. Plaza Hospital (DOPH) from 2009 to 2016 in Agusan del Sur where RV vaccine was introduced in the immunization program; and in Cotabato Regional Medical Center (CRMC) from 2011 to 2016 in a region where the vaccine was not introduced. Reports from consultations in public health clinics in Agusan Del Sur and RV vaccine coverage were obtained.

Results: All-cause diarrheal admissions among children <5 years old in DOPH declined from 2013 to 2016 following RV vaccine introduction in 2012. Using the 2009-2011 mean number of hospitalizations as baseline (X‾ = 1,141), the reductions were 28% (n = 821), 56% (n = 507), 63% (n = 417) and 59% (n = 466) in 2013, 2014, 2015 and 2016, respectively. In comparison, no substantial declines in diarrheal hospitalizations were seen in CRMC from 2011 to 2016. A declining trend was also seen in outpatient consultations in Agusan del Sur following RV vaccine introduction with declines of 27% (n = 2,333), 33% (n = 2,143), 45% (n = 1,764) and 67% (n = 1,059) in 2013, 2014, 2015 and 2016. From September 2012 to December 2016, the 1 and 2-dose RV vaccine coverage gradually increased from 5% and 4% in 2012 to 92% and 88% in 2015, but decreased in 2016 to 53% and 52%, respectively.

Discussion: RV vaccine introduction was associated with a substantial decline in diarrheal hospitalizations and outpatient consultations for diarrhea in Agusan del Sur, Philippines.