Interrupted time series analysis of trends in paediatric admissions with diarrhea and dehydration following introduction of routine rotavirus vaccine in thirteen Kenyan hospitals

Abstract

Diarrhea and dehydration has been reported to be among the top causes of hospitalization and mortality in children aged under 5 years. Most cases of diarrhea in childhood are caused by rotavirus and routine introduction of rotavirus vaccine has been promoted to potentially reduce incidence and severity of diarrhea and dehydration in vaccinated infants. I examined changes in admissions of all clinical cases of diarrhea and dehydration following introduction of routine vaccination with rotavirus vaccine in 2014 in Kenya. Previously studies have mostly examined changes in admissions with stools positive for rotavirus. This study assessed changes in admissions due to all-cause diarrhea and dehydration without considering whether the patient was tested for rotavirus or not. This was a retrospective observational study that used data from 13 public hospitals currently involved in a clinical network (Clinical Information Network (CIN)) set up to ensure improved collection of routine data to improve inpatient care in Kenya. The hospitals were purposefully selected by the ministry of health to represent different geographical locations in Kenya. I included data for children aged 2-36 months, the age most vulnerable to rotavirus infection. Simulations were used to determine whether the sample size yielded enough power to detect changes in admissions to diarrhea and dehydration. I used interrupted time series analysis model following a negative binomial distribution to assess changes in the burden of diarrhea and dehydration. I used 3 pairs of Fourier terms to account for seasonality of infectious diarrhea admissions. Non febrile admissions (surgical or burns) were used as controls There were 29,231 patients who were classified to be having diarrhoea as well as dehydration. The average DAD admissions per month before the vaccine was introduced (July 2014) was 35 (standard deviation (SD): ±22) and 17 (SD: ±12) after vaccine introduction. Fitting a Segmented regression analysis model revealed a 28.32% (95% C.I, 0.786 to 0.950) decrease in hospital admissions immediately after July 2014 when the vaccine was introduced to the Kenya routine childhood immunization program. This was followed by a 3.00% (95% C.I, 0.786 to 0.950) decrease in month to month hospital admissions due to allcause diarrhea and dehydration after vaccine introduction. There was statistically significant change in admissions from non-febrile admissions before and after vaccine introduction. In conclusion, the introduction of the rotavirus vaccine resulted in a reduction in public hospital admissions because of all-cause diarrhoea and dehydration. It is therefore recommended that continuous monitoring be done to ensure that its performance over time is known.