Data from Public Health England showed a monthly drop in measles cases to 113 in June, including five in Yorkshire, down from 193 in May and 299 in April.
There have been 77 cases so far in the region this year, a third in North Yorkshire.
The drop follows a nationwide rollout of a programme to vaccinate children aged 10 to 16 who never had the jab as toddlers.
Now-discredited research published in 1998 suggesting a link between the measles, mumps and rubella (MMR) vaccine and autism led to a dramatic decline in the number of vaccinations.
The new data shows almost 60,000 previously unvaccinated children aged 10 to 16 have now had one dose of the vaccine. Overall, 67,000 have had two doses.
But officials are still keen to target hundreds of thousands more children who have never had the MMR vaccine or only had one dose.
The overall aim is to vaccinate around 300,000 10- to 16-year-olds who have never had MMR.
Mary Ramsay, head of immunisation at Public Health England, said: “It is still too early to be confident that the drop in cases has come from the campaign but we are making good progress towards the 95 per cent target.”