The measles outbreak in Texas continues to grow, with XXX cases now reported in the South Plains ... [+] region. Fear of spread has increased, too, with people in south-central Texas alerted. (Photo by CDC via Getty Images)Getty ImagesThe measles outbreak in western Texas now has ballooned to 124 cases, according to data released on Tuesday by the Texas Department of State Health Services. This represents an increase of 66 cases since last Tuesday, and officials warn that the outbreak will continue to spread locally and may spread more broadly.Indeed, public health officials on Monday issued an alert for people in south-central Texas. A Gaines County resident recently diagnosed with measles visited Texas State University, UT San Antonio and several other public locations in San Marcos and San Antonio between Feb. 14 and Feb. 16. In the TDSHS alert, officials note that the person was contagious during the trip and may have exposed other individuals to the virus. People who may have been exposed should monitor their conditions, especially if they are unvaccinated.There have been 80 cases reported in Gaines County and 21 in Terry County. Additional cases have been reported in Dallam, Dawson, Ector, Lubbock, Lynn, Martin and Yoakum counties. Thirty-nine of the cases have been in children under the age of 5, while 62 cases have been in people between the ages of 5 and 17. People who were unvaccinated or whose vaccine status is unknown account for 119 cases. Public health officials in New Mexico have reported nine cases in that state, all within Lea County. Although Lea County borders Gaines County, it has not yet been shown that the two outbreaks are linked.The measles vaccine, administered as part of the measles mumps rubella vaccine, is very safe and highly effective. Indeed, public health officials announced in 2000 that widespread vaccination ended the sustained transmission of measles in the United States. Only sporadic outbreaks now occur.However, the vaccine does not provide 100% protection. Studies have shown that its about 97% effective, but what does that actually mean? Basically, people who are vaccinated are 97% less likely than people who are unvaccinated to get measles, assuming that people in both groups are exposed similarly. Lets look at it another way. If 100 people in an unvaccinated group develop measles, then only three people in a vaccinated group should develop measles. And vaccinated patients tend to have milder symptoms and are less likely to transmit the virus to others.Of course, myriad factors, including the underlying health of an individual, a persons age or the extent of exposure all can influence the outcome in a specific person. But the general trend holds: This vaccine is incredibly effective.Still, a risk to vaccinated people does exist. For example, about 5% of the patients in a large 2018 outbreak in New York City were vaccinated. And although most cases in Texas have occurred in unvaccinated people, five cases have been reported in vaccinated individuals.Increasingly, vaccine deniers are using a personal choice framework to argue against vaccine requirements. Indeed, when asked about vaccines in 2024, Robert F. Kennedy, Jr., now the secretary of the Department of Health and Human Services, stated that, people can make individual assessments about whether that product is going to be good for them. But its not simple. One persons decision to forego a safe and effective vaccine could affect multiple people in tragic ways, including infants too young to be vaccinated or those who are immunocompromised.Decreasing vaccination rates negatively affect all of us.