According to NBC News data, more than 800 people in the United States have had measles since the beginning of the year. Most cases are found in western Texas, where an outbreak that does not show signs of decrease began in January.
Almost all cases are among people who have not been vaccinated, but 3% of the cases identified are the so -called innovative infections. People got sick despite being partially or completely vaccinated with measles shot, paper and rubella (MMR).
Infectious diseases doctors strive to emphasize that the MMR vaccine is one of the most effective vaccines in the market, but as Rodney Rohde, professor at Texas State University, a small number of people who are completely vaccinated can get sick during a large outbreak.
A dose of the MMR vaccine is 93% effective to prevent measles, and the second dose increases to 97%.
“The vaccine is highly effective,” said Rohde. “But it means that after two doses, while 97 out of every 100 people will develop a strong immunity and will be protected if they are exposed to measles, the three out of 100 remaining could still be vulnerable.”
The last outbreak has seen that claims circulate on the social networks of people who say they are completely vaccinated and that they still hire an innovative infection, which makes them seriously bad, something that Rohde said it is “slightly possible.” “They could fall into one of those small percentages that obtained the complete vaccine but simply did not respond,” he says.
However, he said, it is also plausible that these people have not realized that they were not completely vaccinated against measles. The research suggests that when innovative infections occur, the MMR vaccine still tends to provide some partial protection. “If someone vaccinated receives measles, it is often a softer version, sometimes called modified measles,” says Rohde. “An eruption can still occur, but it may be less widespread [across the body]Weaker or atypical, which means that the classic pattern of starting in the hair line does not follow and extending down. The fever is also less common or smaller. In classic measles, fevers can increase more than 104 degrees Fahrenheit, but in modified cases, it is often softer or more absent. “
According to Rohde, the same is true for other common measles symptoms:
- Cough
- Rhinorrhea
- Conjunctivitis or red eyes
“They can still happen, but they are often less intense,” he says. “Koplik spots, which are small white spots in the mouth, look less frequently. Innovative cases are also generally less contagious, but even a potential transmission source.”
People are contagious four days before and four days after the eruption begins, according to the Texas State Health Services Department. The eruption usually appears 14 days after the exhibition.
Rohde also suggests that people who experience serious symptoms of an innovative infection may have had a single dose of vaccine, which still offers significant protection, but not as much as the complete two dose regime. “These cases may be closer to classic measles than in the advances of two doses, with a high fever that can last longer,” he says. “The eruption is usually a more typical measles eruption and can be more extensive than in innovative cases totally vaccinated. It is also more likely that they obtain possible complications.”
There is still the question of why these infections happen.
As Rohde and others explain, there may be a series of reasons, from the moment of vaccination to genetic variability in the immune response.
The immunity of the measles vaccine is mostly stable
While the Secretary of Health and Human Services, Robert F. Kennedy Jr., has asked the public to vaccinate measles, also said in an interview with CBS News that “the vaccine decreases very quickly.”
Vaccine experts contaminate that MMR shots offer protection for a lifetime.
“If immunity decreased a lot, I would see many cases in people vaccinated in older groups, and we are not seeing that in this Texas outbreak or any other in the recent past,” said Scott Weaver, a professor of microbiology and immunology in the medical branch of the University of Texas, which also works with the coalition of experts in the global virus network of experts. “People seem to be solidly protected, and almost all for life, for what we can say.”
Unlike influenza or covid, measles is a very stable virus that has evolved little to evade immunity induced by the vaccine over time. In 2021, Mayo Clinic researchers published a study concluding that there is an almost zero probability of a new measles virus that emerges naturally with the ability to avoid the MMR vaccine.
While the virus is not changing, it seems that in some rare cases, the body’s own immune system can stop producing antibodies against the virus. According to international studies, scientists have concluded that it is possible that some children vaccinated against measles lose their protection in the course of two decades.
“Because measles is highly infectious, it is expected that this waning causes some innovative infections,” said Alexis Robert, a researcher at the London School of Hygiene and Tropical Medicine, author of an article on the protection of long -term vaccines in 2024.
All people respond to vaccines or natural infections in a slightly different way, according to Weaver.
The MMR vaccine, which works when presenting the immune system with a living but weakened version of the measles virus, trains the body’s immune cells to recognize different parts of the virus proteins called epitopes and generate antibodies against them in the future, he said.
An epitope refers to small amino acid segments in the structure of a protein that the immune system antibodies learn to recognize and join, if the virus tries to invade again in the future.
It is not unexpected for some people to respond badly to any vaccine, said Weaver.
“Some people have a very robust response because they respond to many different [viral] The epitopes, and some people, by chance, have immune cells that cannot recognize so many of those epitakes, “he said.” The differences in our genetic composition determine how many different epitopes we respond and develop immune memory. “
After measles was declared eliminated in the United States in 2000 and was no longer considered a threat to public health, research on the virus slowed down. With the increase in the vaccine vaccine and the United States near losing their measles elimination state, some scientists see the need to study and monitor rare cases of innovative infections.
“While transmission patterns show measles outbreaks are driven by groups of unnoticed individuals, especially among children, a potential risk of infection years after vaccination still affects which strategy is more effective and the coverage necessary to eradicate measles,” Robert said.
How fast is the measles vaccine in force?
Time can also make a difference. A boy who had just received the MMR vaccine will remain vulnerable to measles in the first weeks, especially during an intense outbreak where a lot of viruses circulates, said Rohde.
“In most cases, the human immune system takes approximately two weeks to develop sufficient protection against measles virus and many other pathogens,” he said. “If you were exposed just before or after receiving the vaccine, your body may not be with full force.”
In some cases, for example, people born with a weakened immune system or develop conditions such as autoimmune diseases or blood cancers, the body may not mount an effective immune response against measles, resulting in innovative infections.
“There are people who only have a general immune system that is not so effective against many different infectious agents,” said Weaver. “We know about people who are immune committed for certain reasons, as they are infected with HIV, they are under chemotherapy for cancer, things like that, but there are some people who are only born with immune systems that do not work so well.”
Another plausible explanation is that people may have received a defective MMR vaccine, although Weaver said this is unlikely in the United States, where quality controls tend to be quite strict.
“In cases of measles, it is a live virus, so that the virus can become less infectious if it is not stored correctly and that could lead to less [immune] Answer, ”he said.
When you may need measles reinforcement
If you are more vulnerable to developing an innovative measles infection, it could also depend on when you were born. Before the first measles vaccines were developed in the 1960s, practically all contracted the virus during childhood, providing those who survived the immunity for life.
However, people who were born between 1957 and 1968 received a first -generation meas -generated measles vaccine using an inactivated virus that did not work so well. The centers for disease control and prevention recommend that any person born within this period of time obtain at least one dose of MMR.
Between 1968 and 1989, most people received only one dose of MMR, making them a little less well protected compared to the people who obtained the two standard doses in the last 36 years.
Dr. William Schaffner, professor of preventive medicine and infectious diseases at the University of Vanderbilt Medicine, suggested that if someone who only obtained a dose is close to a current measles outbreak or travel internationally to a country where the virus is endemic, it could be worth seeing with a doctor about getting another dose.
“Even if you are really immune and get another dose of MMR, there is no damage to that,” said Schaffner.
