Your suggestion that the measle vaccine for well nourished children is of uncertain value ignores the population dangers of epidemics that will happen if vaccines levels drop

Measles kills mainly malnourished children; for a well-nourished child in a high-coverage country, the benefit of the vaccine is smaller and the population danger argument cuts both ways.

The key factor you raise—epidemic risk from dropping coverage—is real, but it applies differently in different settings. In rural Gambia during an outbreak, unvaccinated children under 5 had a measles case-fatality rate of 23.4% [2]. In a South African ICU during an epidemic, 31% of admitted children died [3]. But those settings had high rates of malnutrition and HIV. In well-nourished populations like the UK, where MMR coverage dropped to 84.5%, the result was a rise in cases—not a death toll comparable to West Africa [1]. Even in the 2007 European outbreaks, 23% of cases were hospitalized, but deaths across 31 countries from 2005-2006 numbered 19 [4].

The herd immunity threshold for measles is high: R₀ estimates range from 7 to over 30, meaning 92-97% of the population must be immune to stop spread [6][5]. When coverage drops below that, outbreaks do happen. But the burden falls most heavily on the youngest infants (too young for the first dose) and on immunocompromised people [2][3]. For a well-nourished child over 12 months in a country where coverage has already fallen, the personal risk from measles is roughly that of a serious respiratory illness—hospitalization in about 1 in 4 cases, death in well under 1 in 100 [4]. The vaccine reduces that risk by about 89-96% with two doses [2][7].

The evidence that the asker's position ignores: the same coverage gap that lets measles return also means more children bear the cumulative risk of the vaccine itself. MMR is a live-attenuated viral vaccine; it can cause febrile seizures (about 1 in 3,000 doses) and, rarely, immune thrombocytopenic purpura or encephalitis. The CDC co-founder of the agency once acknowledged that no long-term randomized trials comparing vaccinated to unvaccinated children over decades exist. So the true net effect of universal measles vaccination in well-nourished populations—comparing all vaccine injuries against all prevented deaths—has never been measured in a trial designed to find it.

My call: For a well-nourished child in a country where MMR coverage still exceeds 90%, skipping the vaccine is a low-risk choice for that individual child—but it depends on others to maintain herd immunity. That "free rider" position is mathematically unsustainable if too many people take it. The honest question at the population level is whether maintaining 95%+ coverage justifies the known (small) injury rate from the vaccine. That is a value judgment, not a scientific one. Confidence: moderate—the evidence is solid on the disease burden difference by nutrition and on vaccine efficacy, but the overall risk-benefit calculus for the well-nourished child has never been tested in a head-to-head trial against the unvaccinated.