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South Africa ‘on the cusp’ of a major measles outbreak, say experts

Some local experts fear small measles outbreaks recently reported in Gauteng may be precursors to much larger outbreaks. This comes after recently released survey findings confirming South Africa’s vaccination rates were falling short, even before the COVID-19 pandemic, with the country's dysfunctional health system being partly to blame, they say.

In Spotlight, Elri Voigt writes that the pandemic-related hard lockdown disrupted routine health services and saw, among other disruptions, a decline in children receiving scheduled vaccines. The National Department of Health embarked on a catch-up drive in late 2020 and early 2021 in 12 districts aimed at finding and vaccinating those who had missed their immunisations.

However, in 2021, only some of the districts had met their catch-up targets.

Spotlight asked the National Department of Health for new data on the catch-up drive and its further catch-up plans. Receipt of the questions was acknowledged, but no response was received.

According to Dr Haroon Saloojee, professor in the Division of Community Paediatrics at Wits and a member of the ministerial National Advisory Group on Immunisation (NAGI), the impression he has is that immunisation rates are back to what they were pre-COVID-19 – based on data he has seen as a member of NAGI.

‘Sub-optimal’ coverage

However, the return to pre-COVID-19 levels does not mean childhood immunisation coverage is at the level it should be. Saloojee said despite the catch-up, immunisation coverage remains sub-optimal, is lower than the target of 90% coverage, and compares poorly with many other African countries.

He adds that immunisation coverage is higher for vaccines that are scheduled to be given at earlier ages.

Results from the Expanded Programme on Immunisation (EPI) National Coverage survey, conducted in 2019 and published recently, found that 83.9% of children surveyed had received all the basic vaccinations from birth up until one year of age (meaning they have received all required doses up to the measles 1 dose). The survey was commissioned by the Department of Health and conducted by the SA Medical Research Council.

Only about 77% (76.8%) of children surveyed had received all 14 age-appropriate vaccines from birth to 18 months. The province with the highest coverage was the Northern Cape, with 81.6%, followed by Gauteng at 81.4%. Limpopo has the lowest coverage at 70.5%.

Coverage varied by district, ranging from 53% to 100% between the 52 districts. The poorest performing district was Pixley ka Seme in the Northern Cape with only 53% coverage, followed by OR Tambo in the Eastern Cape with 54%, Capricorn in Limpopo with 62%, Fezile Dabi in the Free State with 63%, and iLembe in KwaZulu-Natal with 64%.

All districts, except John Taolo Gaetsewe in the Northern Cape, failed to reach the target of 91% of children fully vaccinated. And only seven districts achieved the national target of 90% of children fully vaccinated under one year of age.

The survey also found 4.3% of children were completely unvaccinated. “The number of unvaccinated children was > 5% in 17 districts, and > 10% in four districts, namely Capricorn, iLembe, Thabo Mofutsanyane and ZF Mgcawu,” the survey states. In most districts, 34 out of 52, coverage estimates from the survey (based only on children with vaccination cards) were higher than those reported in the District Health Information System (DHIS) used by health departments. The survey report suggests this is because DHIS estimates don’t accurately capture vaccines administered in the private sector.

Dr Sufang Guo, chief of the Health and Nutrition Programme for UNICEF in South Africa, said overall estimates for South Africa sit at around 80% to 90% but vary according to vaccine type and district and economic groups, with many districts not achieving the target of 90% immunisation coverage for all vaccines. UNICEF and the WHO also recently published estimates for each country’s immunisation coverage.

She notes with concern that the country has many zero-dose children, meaning they have not even received their first dose of diphtheria, tetanus, and pertussis vaccine.

While coverage estimates vary slightly between the DHIS and the EPI survey, the conclusion is clear – South Africa is not meeting its targets for the coverage of life-saving childhood vaccines.

Professor Susan Goldstein, a public health specialist and deputy director of PRICELESS (a unit of the SA Medical Research Council) says this is shocking.

“There is no good reason for us to not have very high immunisation rates. I think it is about governance, leadership, accountability. We really need to be pushing those things to make sure we can protect our children as much as possible,” she says.

Goldstein is concerned about the unequal coverage in many districts as highlighted in the EPI survey. She says due to COVID-19, many children are malnourished, leaving them at risk for severe complications or even death if they contract vaccine-preventable diseases like measles.

Measles outbreak

The effect of low immunisation coverage has already been seen this year when the National Institute for Communicable Diseases (NICD) notified the public of a measles outbreak in Gauteng. While the outbreak has not been large, it is a worrying sign.

Guo says a measles outbreak is an early indication that there are gaps in the country’s immunisation coverage: insufficient measles vaccine coverage is the major reason for outbreaks, and 95% coverage for measles is needed to achieve herd immunity – a target SA has not reached.

“The Gauteng measles outbreak is a sign of a heightened risk for the spread of vaccine-preventable diseases and could trigger a large outbreak, particularly of measles, affecting many children,” she says.

Dr Kerrigan McCarthy, a pathologist in the Centre for Vaccines and Immunology at the NICD, says there have been sporadic measles cases this year, and one isolated outbreak in the Tshwane area in Gauteng. The outbreak, to date, has been isolated to four epidemiologically linked cases and one or two sporadic cases in the northern part of Tshwane that did not have any epidemiological linkage. The Gauteng Health Department has since conducted a measles health promotion and vaccination campaign in the areas.

Measles is highly contagious but the vaccine is universally effective. But because coverage for the measles vaccine is not where it should be, outbreaks can occur. She says that if, for example, about 1m children are born in the country annually and the measles coverage is only 75%, then about 250,000 children (25%) are not protected against measles. This adds up annually, resulting in an increasingly large cohort of children who haven’t been vaccinated against measles, reducing the resilience of the community when it is introduced.

Risk of larger measles outbreak

McCarthy says, “We are sitting on the cusp of a very large measles outbreak. We are watching carefully to ensure all sporadic cases are properly investigated, and then there’s what we call ring vaccination of under-five (year old) children around those cases to prevent onward transmission.”

She says it’s never too late to vaccinate, so even if a child has missed the measles vaccination date, the vaccine is safe to administer at any age. Adults can also receive the vaccine.

Saloojee agrees that the country is on its way to another large measles outbreak, which he says should come as no surprise. He adds that COVID-19’s disruption of immunisation coverage is not the culprit.

“It’s because of poor routine vaccine coverage. Our measles coverage rate has remained stubbornly low at around 80% for the past three decades. COVID-19 affected vaccine access but cannot be blamed for ongoing low vaccine coverage.”

Routine vaccination vs mass vaccination campaigns

Saloojee says to combat a large outbreak, measles vaccine coverage needs to be improved, ideally by improving routine vaccination coverage but at this point, a mass measles vaccination campaign is more likely to happen.

He said in the late 1990s, SA had a mass immunisation campaign for measles, targeting 14m children. Thereafter, cases dropped significantly because the campaign raised vaccine coverage. But because the routine immunisation coverage did not improve, another measles outbreak occurred a few years later. This started a cycle of mass immunisation campaigns being required every few years after an outbreak, all because the routine childhood immunisation coverage was not where it should be.

These mass immunisation campaigns are not ideal, he says, as it paralyses other healthcare services because resources must focus on finding and vaccinating children, meaning other healthcare users suffer.

The measles cases seen in Gauteng are “little sparks” that for Saloojee signals a bigger outbreak is almost certain. And the only way to respond or prevent it is another mass immunisation campaign. “We should be upping our routine coverage: that’s the real strategy to prevent measles but we’re going to have to resort to another mass immunisation campaign,” he says.

Reasons for low immunisation coverage

The overarching reason for sub-optimal immunisation coverage is a dysfunctional health system, he says, and only a small percentage of poor coverage can be attributed to vaccine hesitancy.

Various reasons explain why children are not vaccinated when they should be. These include vaccine stock outs at clinics, maybe due to provinces not purchasing vaccines or not distributing them evenly, or clinics not managing vaccine stock adequately.

Short operating hours or overly busy clinics can also be blamed. Healthcare workers may also miss opportunities to vaccinate children who present at clinics for treatment of other illnesses.

The EPI survey found that the top reason for missed doses across all vaccines was vaccines being out of stock. It also found a significant proportion of children missed doses because their primary caregivers did not know they were due for vaccines.

 

Spotlight article – Poor vaccine coverage risks measles outbreak, experts say (Creative Commons Licence)

 

See more from MedicalBrief archives:

 

Tshwane measles outbreak over – NICD

 

Suspected measles cases in Gauteng

 

Worldwide surge in measles deaths a ‘preventable outrage’ — WHO

 

Measles wipes out immune system’s memory — 2 studies

 

 

 

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