Prof Aldous: 5,037 measles cases. Is the response working? Nobody can say yet

South Africa has now confirmed 5,037 measles cases this year. We know that because the NICD counts them. What we don't know is whether the vaccination drive is actually working. In her third piece for BizNews on the outbreak, Professor Colleen Aldous argues that national totals and dose counts show effort, not effect. Thousands of jabs can still miss the zero-dose children most at risk. What she's asking for is simple: publish the denominators, district by district. Who was targeted, who was reached, and what happened next. Without that, nobody can claim success. Or failure. Isn't that worth knowing before the next campaign?.By Professor Colleen Aldous.South Africa recorded 5,037 laboratory-confirmed measles cases between 29 December 2025 and 13 September 2026, according to the National Institute for Communicable Diseases (NICD). That number demands attention. It does not, on its own, tell us whether the public-health response is working.This is the third question in a series I have raised about the outbreak. First, why are children missing vaccination? Then, as transmission moved between districts and involved different age groups, was the response moving with it? We must now ask what happened after interventions were deployed. How many susceptible people were reached, and what happened to local transmission thereafter?An outbreak can continue even when vaccination campaigns prevent many additional cases. Equally, a large campaign can record thousands of doses while missing the children most likely to be exposed. Neither the national case total nor a campaign's dose count settles the matter.What the latest figures can tell usThe NICD's total is cumulative and is based on laboratory confirmations. Its weekly reports caution that the figures are influenced by specimens received and tested. We should therefore avoid describing the difference between two published totals as the number of people newly infected in that interval. Confirmation dates and infection dates are different things. Earlier figures can also be revised.The two earlier articles tracked totals of 3,891 through 16 August and 4,188 through 30 August. The latest total is 849 more than the last figure. This is a substantial increase in the reported cumulative burden, but it is not a valid calculation of incidence over two weeks. The finer questions require an epidemic curve by date of rash onset, broken down by district and age.Measles spreads readily wherever susceptible people cluster. A national total can conceal one district where transmission is falling and another where it has only just taken hold. The previous NICD report showed that pattern clearly. Its four-week district counts included Cape Town, John Taolo Gaetsewe (Kuruman-Kathu area of the Northern Cape), Mopani (in Limpopo Province), Tshwane and Thabo Mofutsanyana (Eastern Free State), while Johannesburg recorded no new confirmed cases in the same period despite a substantial earlier burden. That is precisely why provincial totals alone are an inadequate guide to action.Campaign activity is evidence of action, not yet evidence of effectHealth authorities have undertaken catch-up and targeted vaccination. In my previous article I cited the Western Cape's report that targeted campaigns between October 2025 and March 2026 had vaccinated 39,939 people in affected areas. That is a meaningful operational achievement. Yet it is impossible to calculate campaign coverage without knowing the eligible population in each affected area, including people already vaccinated, children who have missed all routine doses and those whose vaccination status is uncertain.Nor can we infer failure because subsequent cases were detected in Cape Town. Campaigns may have prevented many infections that would otherwise have occurred. A fall in cases after vaccination would be encouraging, but it could also reflect changes in exposure, local transmission dynamics, reporting or the epidemic's natural course. The question requires careful local analysis, preferably comparing the timing and reach of interventions with subsequent onset-based curves and patterns in nearby comparable areas.I have not found a single public, district-by-district account that joins those pieces together for this outbreak. That is a statement about the material available for public scrutiny, not a claim that district teams are failing to collect the data. Frontline teams may know far more than a weekly national bulletin can convey.Publish the denominatorsA useful district report would give the date and geographic boundaries of each campaign, the intended age groups, the estimated target population and how that estimate was obtained, the numbers vaccinated by age and prior vaccination status, and the proportion of the intended group actually reached. It would then show the local epidemic curve before and after the intervention, while marking reporting delays and any simultaneous measures.We should also know whether confirmed cases had received no doses, one dose or two doses, acknowledging missing records and the interval since vaccination. These figures must be handled fairly. A case's vaccination status is not a vaccine-effectiveness estimate unless the vaccinated and unvaccinated populations at risk are also known. But it can help locate gaps and guide the next response.If campaign teams reach mostly children who already had documented doses, while zero-dose children remain outside the system, a high number of vaccinations can coexist with a persistent outbreak. If a district rapidly finds and vaccinates previously missed children and transmission then declines, we have a more informative account of possible benefit. Neither inference is certain without further analysis, but both are more useful than a national count alone.The same principle applies to age. My previous article noted that more than one in five confirmed cases in the report through 30 August occurred in people older than 15. This does not automatically justify a general adult campaign. It does justify examining where those cases cluster, whether their vaccination histories are known and whether the local risk assessment calls for a different target group. Young infants, including some too young to have received a routine dose, also depend on protection in the surrounding community.An accountability measure that helps the responsePublishing intervention results is a practical way to improve public health. District teams can see whether their target estimates were realistic. Provincial managers can redirect staff and vaccine supply to communities still being missed. Parents can understand why a campaign covers a particular age range or area. Researchers can help distinguish an apparently unsuccessful intervention from one that prevented a worse outbreak. This should be done with care e.g. avoiding small-cell reporting which can compromise privacy. Low coverage may also reflect difficult geography or an inaccurate denominator rather than poor work by a clinic. Local data should support improvement, with explanations alongside numbers, rather than become a league table that punishes those serving the hardest-to-reach communities..Read more:.Prof Colleen Aldous: Measles is moving through South Africa. Is our response moving with it?.South Africa has laboratory surveillance to tell us where measles is confirmed. It has the capacity to report what was done in response. Joining those two accounts would allow a more honest answer to the question now before us. We may find examples of campaigns working well and others that need changing. For the moment, the public record is too incomplete to say either that the response has controlled this outbreak or that it has failed.The measure of success is not how many cases we can count, or how many doses we can announce. It is whether children and other susceptible people who were at risk have been protected, and whether local transmission has then been brought under control..Sign up for your early morning brew of the BizNews Insider to keep you up to speed with the content that matters. The newsletter will land in your inbox every morning on weekdays. Register here.Support South Africa's bastion of independent journalism, offering balanced insights on investments, business, and the political economy, by joining BizNews Premium. Register here.If you prefer WhatsApp for updates, sign up to the BizNews channel here.

Prof Aldous: 5,037 measles cases. Is the response working? Nobody can say yet

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