Resurgence of measles cases and determinants of measles infection in Zambia: Data from 2016-2025

Background

Despite ongoing vaccination efforts, Zambia has experienced recurrent outbreaks of measles in recent years. This study aimed to assess measles incidence, epidemiological trends and identify determinants of measles infection in Zambia to formulate effective strategies for targeted interventions.

Methods

This study used a retrospective cross-sectional study design. This was carried out using data obtained from the national surveillance database reported from January 2016 to December 2025. The variables extracted included age, sex, date of onset, vaccination status, case location, measles IgM test result and recovery outcomes. Data were analyzed using SPSS version 25 for descriptive statistics, trend analysis and logistic regression.

Results

A total of 6,112 measles cases were reported and tested. Of them, 1,601 (26.2%) were laboratory confirmed measles cases. The most affected age group was 1-4 years with 35.3% cases followed by 5-9 years with 30.6% cases. Majority of cases were reported from Lusaka 969 (15.9%) and Northwestern 837 (13.7%) provinces. The cumulative measles incidence rate in Zambia over ten years was 8.13 cases per 100,000 population. The incidence rate was highest in 2023 with 3.16 per 100,000 and lowest in 2016 with 0.25 per 100,000 population. The highest average annual incidence rate was recorded among the <1 year (32.75 per 100,000). Determinant factors for measles infection were, age < 1 year, 5-9 years, female sex, being unvaccinated and unknown vaccination status were significantly associated.

Conclusions

The burden and cumulative incidence rate of measles in Zambia were high, putting the country off track for measles elimination. The significant measles incidence was increased among under-immunized populations, under five children, females and international border province as a contributing factor that warrants strengthening routine immunization, enhancing public awareness, improving healthcare access and regional coordination.

Key messages

• This study critically assessed the measles incidence, epidemiological trends and identify associated factors for measles resurgence in Zambia.

• The findings of this study inform national and international public health programmers and policymakers to develop targeted interventions and improved measles prevention and control strategies.