Measles Outbreaks in the US
At least 3% of the measles cases confirmed so far were in people who have received two measles vaccine doses, meaning they were fully vaccinated, according to the Centers for Disease Control and Prevention (CDC). About three dozen of the almost 1,200 measles infections were in people with two vaccine doses. Another 2% of cases were in people who received at least one dose of measles vaccine.
Vaccination Status
Many of the cases were in Texas, where a 21st confirmed measles case was counted on Tuesday in someone with at least two doses of the vaccine. A CDC spokesman said that the data reflects the vaccination status at the time of exposure, meaning that none of the 36 vaccinated cases confirmed had received post-exposure prophylaxis. Post-exposure prophylaxis offers someone a medication or vaccine after being exposed to a germ to reduce the likelihood of infection or developing serious illness.
Protection Against Measles
The CDC says that people who are exposed to measles should receive the MMR vaccine within 72 hours of initial exposure if they are not fully immunized. The MMR vaccine can offer some protection against infection or change the clinical course of illness if administered within 72 hours. The CDC spokesman emphasized that the MMR vaccine is the best way to protect against measles and its complications. Symptoms of illness are generally milder among vaccinated people, and people who are vaccinated are also less likely to spread the disease to other people.
Measles Outbreaks and Travel
Texas saw a fatal outbreak of the highly contagious virus this year, and while cases have recently slowed down, CDC officials have announced that authorities are anticipating more outbreaks in other communities in the US connected to travel outside and within the country. Additional cases have been sown from the outbreak in Texas and associated outbreaks in Mexico and Canada. The import of measles from international trips will continue, especially with increasing summer travel.
Hospitalization and Vaccination
None of the confirmed measles cases that led to hospital stays this year had documented evidence that they had received two vaccine doses, said the CDC spokesman. More than 8 in 10 of the cases were in people aged 20 or older. Health authorities and experts have asked some seniors to check whether they need a measles booster, especially if they plan to travel, due to the type of measles vaccines used before 1968.
Measles Vaccine Effectiveness
Measles vaccines are 97% effective in preventing measles after two doses and 93% after one dose, the CDC says. The CDC has published new guidelines for summer camps to prepare for the threat of measles this year, including urging camp operators to check for immunity among employees and children. Many vaccinated cases were in residents who were exposed during travel to other parts of the world with large outbreaks, such as Canada and Europe.
