The number of cases of measles has increased to 58 in the South Plains region of Texas, according to data released by the Texas Department of State Health Services on Tuesday. This represents an increase from 48 cases reported on February 14. Fifteen cases have been in children under the age of 5. An additional 33 cases have occurred in children between the ages of 5 and 17. Thirteen individuals have been hospitalized. Another three cases have been reported in New Mexico. Health officials in Texas report that most of the infected people are unvaccinated or only partially vaccinated.
What Is Measles?
Measles is a highly contagious, severe airborne disease. Typically, people with the disease exhibit a high fever, respiratory symptoms, conjunctivitis, and the tell-tale rash. These symptoms may be mild in some people but can be quite significant. According to the CDC, about 20% of unvaccinated people in the U.S. who get measles require hospitalization. Measles is fatal in approximately one to three out of every 1,000 unvaccinated children. About one out of every 1,000 children will develop swelling of the brain, which can lead to long-term hearing and cognitive problems. Measles also has been associated with long-term defects in the immune system, leading to increased susceptibility to other infections later in life. And, according to the American College of Obstetricians and Gynecologists, measles infection during pregnancy can lead to increased risks of preterm delivery, low birth weight, and miscarriage.
Also called rubeola, measles is caused by the measles virus, a member of the morbillivirus family of viruses. Other pathogens in this group include canine distemper virus, which infects dogs, and rinderpest virus, which infected cattle and related ungulates. A global vaccination program led to the eradication of this disease, with the last reported case of rinderpest occurring in 2001.
Measles virus only infects humans. It is transmitted from person to person via respiratory droplets and is highly transmissible. Epidemiologists generally agree that the R-naught value of this virus in an unvaccinated population is 12-18. In other words, an infected person, on average, will infect an additional 12 to 18 people. This makes measles viruses one of the most contagious viruses known.
Signs and symptoms of disease usually appear about one to two weeks after a person is exposed to the virus. A rash usually becomes noticeable a few days after the onset of the initial symptoms. An infected person can transmit the virus to others beginning about four days before the rash appears and an infected person remains contagious for about four days after the rash first appears. Thus, to prevent the spread of disease, a person with measles should remain in isolation throughout this period.
The Measles Vaccine
Measles can be almost entirely prevented by vaccination. The vaccine, administered in the U.S. as part of the Measles Mumps Rubella vaccine, consists of a weakened, or attenuated form of the virus. Upon injection, this attenuated virus replicates at low levels in a person, stimulating a robust immune response but not causing disease. A two-dose series is recommended, with the first dose being administered in children between the ages of 12 and 15 months and the second dose being administered around 5 years of age. The shots can be administered to older children and adults who were not previously vaccinated. Typically, maximal protection occurs about two weeks after the second dose.
This vaccine is incredibly effective, providing about 97% protection in fully vaccinated people. The result? A dramatic decline in the number of measles cases and deaths occurred during the second half of the 20thcentury. Indeed, measles was declared eliminated from the U.S. in 2020. Sustained spread no longer occurs.
The vaccine also is very safe. Common side effects are mild and may include soreness at the injection site and a low-grade fever. In rare cases, children may experience a seizure, but these seizures have not been associated with any long-term consequences. Studies repeatedly have found no link between the MMR vaccine and the development of autism.
Despite the safety and effectiveness of the MMR vaccine, not everyone can be vaccinated. For example, the vaccine may be contraindicated in people who are immunodeficient. This group could include people with HIV disease and people undergoing chemotherapy treatment. The vaccine also is not recommended for people who currently are pregnant.
What Comes Next?
Because of the relatively low vaccination rate in Gaines County, the number of cases in this outbreak probably will continue to rise. Measles is highly contagious, so all unvaccinated people in the area remain at risk. People who do become infected should isolate until four days after the rash first appeared, to limit the spread to others. And unvaccinated people should get vaccinated. The Texas Department of State Health Services announced that vaccines are available at the South Plains Public Health District Clinic. The discomfort of a shot certainly is less than the severe consequences of the disease.
