Vaccinated people still get sick, so what's the point?
Here is what the checked sources say. Each title links to the original.
Vaccines for measles, mumps, rubella, and varicella in children
A Cochrane review of 138 studies (about 23 million participants). Each estimate comes from a separate, smaller group of studies: measles vaccine was 95% effective after one dose and 96% after two, from different cohorts, so the gap does not measure what a second dose adds. Mumps: 72% and 86%. Chickenpox: 95% after two doses over 10 years. The review also found evidence of rare real harms: febrile seizures in about 1 per 1,150 to 1,700 doses, and low platelets (ITP) in about 1 per 40,000 MMR doses, less often than after natural infection.
Does influenza vaccination attenuate the severity of breakthrough infections? A narrative review and recommendations for further research
A CDC review of 38 studies asked whether people who catch flu despite vaccination get less sick. Among adults hospitalized with flu, vaccination was associated with 26% lower odds of ICU admission (8 studies) and 31% lower odds of death (5 studies). In children with flu, it was associated with 45% lower odds of fever. It was not clearly associated with less pneumonia, or with fewer hospitalizations after outpatient illness. The studies were observational and varied widely, so the authors say the findings support the idea that vaccination may lessen illness.
From Data to Decisions: The Evidence Base for 2026-27 Respiratory Season Immunizations
An independent review of 299 studies, published mostly August 2025 to June 2026, on COVID-19, RSV and flu immunizations. In 2025-26, updated COVID-19 vaccines were 53% effective against hospitalization in adults 65 and older. RSV vaccines were 69 to 83% effective against hospitalization in adults 60 and older; evidence on how long that lasts is mixed. One flu analysis found 31% protection against hospitalization in older adults; another, 80% against flu deaths in children. Safety: one RSV study found a possible Guillain-Barré increase in older adults within 42 days; earlier mRNA schedules carried myocarditis risk, mainly in young males.