SA’s surge in measles cases has been fuelled by the disruption to routine childhood immunisation programmes caused by the coronavirus pandemic, which saw hundreds of thousands of babies miss out on potentially life-saving vaccinations, reveals a new study published in the SA Medical Journal (SAMJ).
The drop in immunisation rates on top of persistently low coverage in some parts of the country has led to a growing pool of susceptible children, say public health experts, contributing to the measles outbreaks declared in Limpopo, the North West, Mpumalanga, Free State and Gauteng.
“There is no question that there are large reservoirs of unvaccinated or under-vaccinated children. This [measles] outbreak was not unexpected,” said the study’s lead author, Yogan Pillay, extraordinary professor at Stellenbosch University’s division of public health and health systems.
“We just have to do better. Almost every province under-budgets for vaccines,” he said, calling for increased surveillance for vaccine-preventable diseases and ring-fenced funding for childhood immunisation programmes.
Limpopo
The SAMJ study shows that while the national vaccination coverage rate recovered to prepandemic levels by the end of 2021, immunisation rates were still below pre-Covid levels in Limpopo (62.4% in 2021 compared with 66.2% in 2019) and the North West (60% in 2021 compared with 64.2% in 2019), the two provinces with the highest measles burdens, according to the National Institute of Communicable Diseases (NICD).
There have been 131 confirmed cases of measles in Limpopo, 80 cases in the North West, 69 in Mpumalanga, 14 in Gauteng and 11 in Free State.
The national vaccination coverage rate fell from 83.5% in 2019 to 80.4% in 2020, and then rose to 84.5% in 2021.
Protecting the population from measles requires 95% of children to be vaccinated, said NICD specialist pathologist Kerrigan McCarthy.
At that level, enough people have antibodies to the virus to prevent the highly transmissible disease from spreading.
The SAMJ study “shows around 800,000 children were fully immunised in 2020. Our SA annual birth cohort is around 1-million; this implies that over 200,000 children in 2020 were unvaccinated,” she said.
“Lower vaccination rates in 2020 exacerbated a pre-existing problem of low vaccination coverage in general and for a number of years prior to 2020. When unvaccinated people accumulate in the population, the proportion of unvaccinated people increases year on year.
“When measles virus is introduced into the population, it becomes harder and harder to prevent onward transmission, because by chance someone in the contact circle of each case will be susceptible,” she said.
The measles vaccine, which government clinics provide free to babies at six months and 12 months, confers lifelong protection and is 97% effective at preventing infection, said McCarthy.
Young babies and severely immuno-compromised adults, such as those with late-stage cancer or advanced, untreated HIV, are at greatest risk of complications from measles, which can prove fatal, she said.
The SAMJ study highlights how other routine public health services were battered by the pandemic, many of which have yet to fully recover.
While many people initially shied away from health facilities for fear of infection, care was also denied to patients as authorities focused on the direct effect of Covid-19.
The research, which builds on a previous study that focused on 2020, shows the number of HIV and tuberculosis tests conducted in 2021 remained below prepandemic levels, as did the number of visits to primary healthcare facilities.
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