Missouri DHSS announces possible measles exposure in St. Louis

JEFFERSON CITY, MO – A confirmed case of measles from an out-of-state resident was reported to have visited the St. Louis Aquarium between 1-6 p.m. on April 30. Additionally, the individual ate at a restaurant in St. Louis on the same day, but available details of this visit have been extremely limited thus far. More details will be provided if they become available. 

Because measles is highly contagious, individuals who may have had exposures at the St. Louis Aquarium during the time the person visited and who are unvaccinated or are immunocompromised should consider post-exposure prophylaxis, according to the established public health recommendation to prevent measles infection and its complications. The usual time interval for prophylaxis to be effective is within six days of exposure (by May 6). Those with questions or the need for evaluation should contact their health care provider or local public health agency. 

All individuals with possible exposures should watch for the symptoms of measles for 21 days from the date of exposure and report to their local public health agency if symptoms appear. People who think they have measles should isolate themselves and call their health care provider before arriving to be tested. It is important to let the provider know of the concern for measles and to get instructions on how to come to the office for diagnosis without exposing other people to the virus. 

Measles is a highly contagious viral illness that typically begins with fever, cough, runny nose and red and watery eyes. One person with measles can easily pass it on to 9 out of 10 people around them who are unvaccinated or do not have natural immunity. Symptoms appear 7-14 days after contact with the virus. Tiny white spots may appear inside the mouth 2-3 days after symptoms begin. Measles rash appears 3 to 5 days after the first symptoms. It usually begins as flat red spots that appear on the face at the hairline. They then spread downward to the neck, trunk, arms, legs and feet. Measles can cause severe health complications, including pneumonia, encephalitis (inflammation of the brain) and death. Measles can be transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs or sneezes. The virus can remain infectious in the air and on surfaces for up to 2 hours after an infected person leaves an area. People who are infected will begin to have symptoms on average 1-2 weeks after being exposed to a person with measles. 

The best way to prevent getting sick is to be immunized with two doses of a measles-containing vaccine, which is primarily administered as the combination measles-mumps-rubella or MMR vaccine. Two doses of the MMR vaccine provide 97 percent protection from measles infections. A small number of vaccinated people can occasionally develop measles. In these cases, the symptoms are generally milder, and they are less likely to have severe disease symptoms and spread the virus to other people. DHSS and the CDC recommend children receive one dose of MMR at 12 to 15 months of age and another at 4 to 6 years. Unvaccinated adults can also receive a “catch-up” MMR vaccination.  

Measles can be especially dangerous for pregnant women and their unborn babies. Children too young to be vaccinated are more likely to have severe complications if they get infected with the measles virus. However, each MMR dose lowers the risk of infection and the severity of illness if infected. 

Health care providers can find recommendations for infection control and diagnostic testing in the health alert issued on March 7. Providers should report any suspected cases to their local health department immediately, preferably while the patient is still with the provider. 

More information about measles and county-level MMR vaccination rates can be found at Health.Mo.Gov/Measles.