With sporadic measles outbreaks continuing to make headlines, many adults wonder whether they need a booster dose of the MMR (measles, mumps, and rubella) vaccine. While the first measles vaccine was introduced in the United States in 1963, its formulation was less potent than the current versions, raising questions about long-term immunity for those vaccinated during the early years.According to health experts, the timing and type of measles vaccine you received in childhood can influence whether a booster shot is necessary. Dr David Cutler, a physician and vaccine specialist, told Medical News Today that immunity status often depends on when you were born and which version of the vaccine you received. "Adults born before 1957 are generally considered immune to measles because they likely contracted and recovered from the disease during childhood," Dr Cutler noted. Natural infection with measles typically provides lifelong immunity.For those born after 1957, the situation is more nuanced. While most people in this group were vaccinated as children, some may have received the original inactivated virus vaccine used between 1963 and 1967. This version is now considered less effective than the live-attenuated vaccine used today.Simple Blood Test Can Help You Determine Whether Booster Is NecessaryTo determine whether a booster is necessary, a simple blood test known as the Immunoglobulin G (IgG) antibody test can assess an individual’s immunity status. "If the test shows sufficient levels of IgG antibodies to measles, that means you are immune," Dr Cutler explained. "If not, a booster may be recommended."In general, a measles vaccine booster may be advisable for:- Children who received only one dose of the MMR vaccine- Adults who were vaccinated with the inactivated version between 1963 and 1967- High-risk adults, such as healthcare workers or international travellers- Anyone whose blood test shows a lack of immunityDr Cutler emphasised that adults who are certain they never had measles, never received the vaccine, and have no health concerns that would contraindicate vaccination should strongly consider getting the MMR shot. With measles being one of the most contagious viruses in the world, maintaining adequate immunity is crucial—not only for personal protection but also to prevent community outbreaks. A simple test or booster could go a long way in safeguarding public health.US Witnesses More Than Double Cases Since 2024The US now has more than double the number of measles cases it saw in all of 2024, with Texas reporting another large jump in cases and hospitalisations on Friday. Other states with active outbreaks—defined as three or more cases—include New Mexico, Kansas, Ohio and Oklahoma. The virus has been spreading in 'undervaccinated' communities, and since February, two unvaccinated people have died from measles-related causes.The multi-state outbreak confirms health experts' fears that the virus will take hold in other U.S. communities with low vaccination rates and that the spread could stretch on for a year. The World Health Organisation (WHO) said last week that cases in Mexico are linked to the Texas outbreak.