A newly published German study has reignited debate over the safety and broader health effects of routine childhood vaccination, challenging the assumption that vaccinated children are necessarily healthier overall than their unvaccinated peers.
The peer-reviewed study, published on July 31, 2026, in the Medical Research Archives, analysed data from 16,662 children aged one to 17 from Germany’s Children’s Health Survey (KiGGS). Researchers compared 202 children who had received no vaccinations with 15,344 vaccinated children.
The authors, Harald Walach and Angelika Müller, reported that unvaccinated children were more likely to have contracted measles, mumps, rubella and pertussis, while vaccinated children showed higher reported rates of chickenpox, scarlet fever and salmonella.
After adjusting for socioeconomic factors and previous diseases, the researchers found an association between the number of vaccinations received and a higher morbidity score. However, the study also reported beneficial associations for some vaccines, including those against measles, polio and hepatitis B.
Importantly, the researchers acknowledged that their analysis was based on cross-sectional data and cannot establish that vaccines caused either better or worse health outcomes. They called for larger, prospective longitudinal studies involving vaccinated and unvaccinated groups.
The findings have emerged amid renewed public controversy over childhood immunisation, particularly following measles outbreaks and debate in the United States over vaccine policy.
Some physicians cited in the debate argue that existing vaccine trials have limitations, including the use of active comparators rather than completely unvaccinated or saline-control groups and insufficient follow-up for some long-term outcomes.
READ ALSO; Pfizer funding trail raises questions over vaccine exemption campaign
However, major public-health organisations maintain that the overall evidence supports routine childhood vaccination.
The World Health Organisation says measles vaccination prevented an estimated 59 million deaths globally between 2000 and 2024. Nevertheless, an estimated 95,000 people, mostly children under five, died from measles in 2024.
The U.S. Centers for Disease Control and Prevention (CDC) says two doses of the measles, mumps and rubella (MMR) vaccine are about 97% effective at preventing measles, compared with about 93% for one dose. It also says serious reactions to MMR are extremely rare.
The CDC acknowledges that MMR can cause febrile seizures in a small number of children—about one in 3,000 to 4,000—but says these seizures have not been associated with long-term effects.
WHO similarly states that vaccines can cause side effects but that serious reactions are extremely rare and that vaccine safety is continuously monitored through national and international surveillance systems.
The German study therefore adds to an ongoing scientific debate but does not, by itself, establish that routine childhood vaccines are more dangerous than the diseases they prevent.
Its authors themselves emphasised the need for stronger prospective research to determine the long-term health differences between vaccinated and unvaccinated children.