Visiting health centers as a risk factor for measles transmission: Kamwenge District, Uganda, April – July 2015
Fred Nsubuga1,&, Lilian Bulage1, Alex Riolexus Ario1
1Uganda Public Health Fellowship Program, Kampala, Uganda
Fred Nsubuga, Uganda Public Health Fellowship Program, Kampala, Uganda
Uganda has been implementing a one-dose measles vaccination at age 9 months in its national EPI schedule. On 27 April 2015, a measles outbreak, which was confirmed by serum positivity in several patients, occurred in Kamwenge District. Since then, the number of reported measles patients has increased despite the implementation of measures to control the outbreak by the local government. We investigated this outbreak to identify the risk factors for measles transmission, estimate vaccination coverage, determine vaccine effectiveness, and recommend control measures.
we defined a probable case as onset in a Kamwenge District resident of fever and generalized rash from 16 April 2015 onward with ≥ 1 of the following: coryza, conjunctivitis, or cough. A confirmed case was a probable case with positive measles-specific IgM in patient serum. For case-finding we reviewed medical records and found patients in the community with the help of the village health team. We determined vaccination histories by vaccination cards or interviews. In a case-control study, we compared the exposure histories of 50 probable case-persons with 200 asymptomatic control-persons during case-persons’ exposure period (i.e., between minimum and maximum incubation). We matched case- and control-persons by age and residence village. We estimated vaccination coverage for children aged ≤ 2 years based on the percent of control-children vaccinated.
we identified 213 probable/confirmed cases from 3 affected sub-counties (attack
rate = 5.1/10,000). The epidemic curve showed sustained community transmission.
The case-control study showed that 42% (21/50) of case-persons and 12% (23/200)
of control-persons visited health centers during case-persons’ exposure period
(AORM-H = 6.1; 95% CI = 2.7-14). Vaccination coverage among children
aged ≤ 2 years was 58% (95% CI = 47-68%). The vaccine effectiveness
was 80% (95% CI = 35-94%). We found that all health centers were crowded,
with no triaging system to separate suspect measles patients from patients
with other illnesses.
exposures to measles patients at crowded health centers, low vaccination coverage, and suboptimal vaccine effectiveness facilitated measles transmission in this outbreak. We recommended an emergency immunization campaign targeting young children, triaging and isolating suspect measles patients at health centers, and introducing a second dose of measles vaccine in the immunization schedule.
The 1st Uganda National Field Epidemiology Conference (Kampala)
The one-day Field Epidemiology Conference took place on December 11th, 2015 at Golf Course Hotel, Kampala. At this conference, Fellows presented investigations and epidemiologic studies they conducted since they joined the Fellowship in January 2015. Through these investigations and studies, important public health problems facing the nation were unveiled and strategies to address them proposed. This conference presented opportunity for national and international experts to discuss and propose solutions. This was the first Field Epidemiology Conference in Uganda and was attended by important dignitaries from the key partner institutions including Ministry of Health, UN agencies, Embassies, University officials, representatives from districts as well as other national and international delegates.
Dates: 11 Dec 2015
Venue: Golf Course Hotel, Kampala
Organizers: Ministry of Health and Makerere University School of Public Health
Contact person: Dr. Alex Riolexus Ario (firstname.lastname@example.org)