Recent cases of measles have been appearing across Texas and concerns about potential exposure have the San Antonio community asking questions.
Jason Bowling, MD, an infectious diseases specialist at UT Health San Antonio and chief epidemiologist at University Health, answers questions about the measles, its transmission and vaccination.
Q: What is the measles?
A: The measles is a highly contagious viral infection that affects humans exclusively. It is primarily transmitted through tiny airborne droplets when an infected person coughs or sneezes. These droplets can remain in the air and on surfaces for up to two hours, allowing the virus to spread rapidly.
Q: Why is measles re-emerging now?
A: Measles was declared eliminated in the U.S. in 2000, thanks to widespread vaccination efforts. However, outbreaks are now occurring due to declining vaccination rates. In some communities, exemptions from vaccination have led to lower herd immunity, increasing the risk of outbreaks. Measles is extremely contagious, and even a small decrease in vaccination coverage can lead to rapid transmission.
Q: Given the recent measles exposure in local communities, how urgent is it to receive the measles vaccine?
A: The measles, mumps, and rubella (MMR) vaccine is extremely effective, providing up to 97% protection with two doses. The current recommendation is that anyone who is unvaccinated or unsure of their vaccination status should get vaccinated to protect themselves and their communities.
Q: Is the vaccine effective immediately?
A: The MMR vaccine starts providing some protection within about two weeks. However, full immunity develops after receiving both doses of the vaccine.
Q: Does the vaccine require a booster for the unvaccinated? If so, how far apart should the doses be given?
A: Yes. For adults who have never been vaccinated, one dose provides about 93% protection. A second dose, given at least 28 days later, increases effectiveness to 97%. Most people who received two doses as children are protected for life and do not need a booster. However, adults who are unsure of their vaccination status should check with their health care provider.
Q: What is the appropriate age for children to receive the vaccine?
A: For children, the standard schedule is one dose at 12 months and another between ages 4 and 6. This two-dose schedule ensures long-term immunity.
Q: What are the side effects of the vaccine? Does it cause symptoms similar to measles, such as a rash?
A: The MMR vaccine is very safe. Some people experience mild side effects, such as a low-grade fever or a temporary rash. However, the rash following a vaccine does not mean the person is contagious with measles.
Q: Can the vaccine still prevent measles if given after exposure?
A: Yes. If administered within 72 hours of exposure, the MMR vaccine may prevent or lessen the severity of measles. Additionally, immune globulin therapy may be recommended for certain high-risk individuals within six days of exposure.
Q: What about expectant mothers? Any special guidance for them?
A: Pregnant women should not receive the MMR vaccine. If a pregnant woman is exposed to measles, she should contact her health care provider immediately.
Q: Where can individuals receive the measles vaccine or a booster?
A: The MMR vaccine is widely available at health care providers’ offices, pharmacies and public health clinics. Supplies are generally sufficient, but individuals should check with their preferred provider to schedule an appointment.
Q: If someone believes they or a family member are infected, who should they contact?
A: Anyone experiencing symptoms should contact their health care provider before visiting a clinic to prevent spreading the virus. Testing can be done through a blood test.
Q: What symptoms should people watch for after exposure?
A: Symptoms usually appear 7–14 days after exposure and include high fever (up to 105°F), cough, runny nose, red and watery eyes, tiny white spots inside the mouth and a rash that starts on the face and spreads downward.
Q: If someone develops a measles rash, does it itch? Can it spread further or leave scars?
A: The rash itself does not typically itch. It spreads as part of the disease progression but does not spread by touch. Unlike chickenpox, measles rashes generally do not scar.
Q: High fevers can accompany measles. When should someone seek hospitalization?
A: While most cases resolve with supportive care, hospitalization may be required if there is difficulty breathing, persistent high fever, severe dehydration or neurological symptoms such as seizures.
Q: Can pets be affected by measles or spread the virus?
A: No. Measles is a human-specific virus and does not affect pets or spread through them.
Bowling stressed the importance of vaccination in preventing the spread of measles. While Bexar County currently has no reported cases, staying informed and up to date on vaccinations is key to community protection.
Anyone who suspects they have been exposed to the measles or has symptoms should avoid public places and make an appointment with their health provider.