Sustained impact of rotavirus vaccine on rotavirus hospitalisations in Lusaka, Zambia, 2009-2016.

BACKGROUND: Monovalent rotavirus vaccine (RV1) was introduced in Lusaka in February 2012 and rolled out countrywide in November 2013 in the routine Expanded Programme on Immunisation and administered at 6 and 10 weeks with no catch up dose. Reported here is the monitoring of rotavirus acute gastroenteritis hospitalisations at the University Teaching Hospital, Lusaka, Zambia as part of efforts to document the impact of rotavirus vaccine. METHODS: Children <5 years hospitalised for acute gastroenteritis (AGE) from January 2009 to December 2016 were recruited into the rotavirus disease burden active surveillance and had their stools tested for rotavirus by enzyme immunoassay. We compared rotavirus-associated AGE hospitalisations of the pre-vaccine era (2009-2011) with the post-rotavirus vaccine introduction period (2013-2016). RESULTS: With the increase in RV1 coverage in Lusaka, rotavirus AGE declined significantly from 40% of diarrhoea hospitalisation in the pre-vaccine era to 29% of diarrhoea hospitalisation in the post-vaccine era (p < 0.001) in children <5 years. After a decreasing trend in rotavirus positivity from 2013 to 2015, positivity increased to 37% in 2016. However, the post-vaccine years (2012-2016) saw substantial decline in the number tested (median decline: 34% (range: 20-43%)) and the number of positive results (median decline: 52% (range: 30-65%). CONCLUSION: A sustained and significant decline in rotavirus AGE hospitalisations was observed in children <5 years since the introduction of RV1 in Lusaka, Zambia. Despite an increase in rotavirus positivity in 2016, the total number of children enrolled and the number of rotavirus positive children remained below baseline. The reason for the increase in rotavirus positivity in 2016 is unknown but could be due to an accumulation of susceptible children and the shifting of disease to children of older age groups. This finding underscores the need for continued monitoring of rotavirus vaccine impact.

CHOLERA EPIDEMIOLOGY IN ZAMBIA FROM 2000 TO 2010: IMPLICATIONS FOR IMPROVING CHOLERA PREVENTION AND CONTROL STRATEGIES IN THE COUNTRY.

OBJECTIVE: To review the cholera epidemiology in Zambia from 2000 to 2010 in order to highlight the key lessons learned. Based on our findings, we make recommendations for improving cholera prevention and control in country. DESIGN: Ten years descriptive cholera data was extracted from the national IDSR database and analysed. SETTING: The study was conducted in Zambia using national epidemiology data which were disaggregated by Province. SUBJECTS: None. RESULTS: Starting from 2003, there has been a progressive increase in yearly incidence of cholera in the country. In 2010, 6794 cases (500% increase compared to 2003) and 115 deaths (CFR 1.6%) of the disease were reported with Lusaka Province accounting for 85% of the total cases. Outbreaks start between epidemiological weeks 40 to 45 of the year and ends between weeks 20 to 25 of the following year (which corresponds to the Zambian rainy season). Outbreaks are largely confined to the peri-urban areas of Lusaka, Luapula, Southern and Copperbelt Provinces. CONCLUSION: In the last 10-20 years, the epidemiology of cholera in Zambia has changed; Laboratory confirmation of Vibrio cholerae in the country on a yearly basis in the last ten years suggests that the country is now endemic for cholera hence the need to review current cholera prevention and control strategies.