Post-Covid immunisation: Childhood measles vaccination rates plunge in several US counties; cases hit 30-year high, study finds

Immunisation coverage for measles among children has declined, after the Covid pandemic in nearly 80 per cent of over 2,000 US counties analysed in a new study. The drop includes several regions currently experiencing outbreaks.The study, conducted by Johns Hopkins University and recently published in JAMA, was cited by the Associated Press. It highlights increased vulnerability in many areas, in line with state and national data showing declining routine childhood vaccination rates."When you look at the state level or national level ... you really don't see those drastic drops. Those are there. They're real and they're really problematic," said Lauren Gardner, the study's senior author and infectious disease modelling specialist at Johns Hopkins University, who also developed the university’s Covid-19 database.As of Friday, the US has recorded 1,088 measles cases in 2025, the highest year-to-date total in more than three decades. The vast majority of cases have affected unvaccinated individuals and have been traced to both international and domestic travel. Three deaths have occurred during the current outbreaks.Although measles was declared eliminated in the US in 2000 due to the availability of a safe and effective vaccine, declining vaccination rates now threaten that status.

All 50 states require two doses of the MMR (measles, mumps, and rubella) vaccine for public school attendance, yet non-medical exemptions reached record highs in the 2023–2024 school year. Experts emphasise that a 95 per cent vaccination rate is necessary to prevent outbreaks.The Johns Hopkins researchers analysed 2,066 counties in 33 states, comparing average kindergarten vaccination coverage from pre-pandemic years (2017–2020) with post-pandemic rates (2022–2024).

When kindergarten-specific data was unavailable, alternative metrics were used to approximate coverage.Outbreaks in affected countiesSince late January, Texas has reported 742 measles cases, most concentrated in West Texas. Gaines County leads with 411 cases, nearly two per cent of its population. Though vaccination coverage rose two percentage points post-pandemic, it remains at just 82.4 per cent, well below herd immunity levels.

Terry and Yoakum counties, with 60 and 20 cases respectively, also fall short of the 95 per cent threshold, at 93.7 per cent and 91.8 per cent.

Lubbock County, near Gaines, reported 53 cases, with coverage slipping from just under 95 per cent to 91.8 per cent. El Paso County, despite maintaining above-threshold coverage at 96.5 per cent, saw a 2.1-point decline alongside 57 reported cases.Kansas has also seen outbreaks.

Gray County reported 25 cases, with vaccination coverage plunging from 94 per cent to 71 per cent. Haskell County saw an 18-point drop to 65 per cent with 11 cases, while Stevens County, with seven cases, dipped to 90.5 per cent.In Colorado, seven cases were traced to a mid-May arrival at Denver International Airport, affecting six residents and one visitor. Arapahoe County logged two cases with coverage at 88.4 per cent.

El Paso County reported three cases and a drop to 80 per cent.North Dakota researchers analysed only post-pandemic years due to limited earlier data. Williams County recorded 16 cases with fluctuating coverage: 84.6 per cent in 2022, 87.7 in 2023, then falling to 83.5 per cent in 2024. Cass County, with seven cases, held steady at around 92.7 per cent. Grand Forks County reported 10 cases, with coverage dropping from 95.4 to 93.4 per cent.