Contagious. measles vaccination rates top 0% in high density cities such as New York, but new data suggest the same immunized can catch and spread. disease
NYCstocker / iStockphoto / Thinkstock; (Inset) Dr. Heinz F. Eichenwald / CDC
Get the vaccine against measles, and you will not be measles or give it to someone else. Right? Well, not always. A person fully vaccinated against measles contracted the disease and transmitted to others. The surprising case study contradicts received wisdom about the vaccine and suggests that a recent wave of measles outbreaks in developed countries could mean more illness, even among the vaccinated.
Regarding the vaccine against measles, two shots are better than one. Most people in the US are first vaccinated against the virus shortly after their first birthday and return to a booster as a toddler. Less than 1% of people who receive the two shots is contracting the potentially deadly skin and respiratory infections. And even if a fully vaccinated person becomes infected, a rare condition known as "vaccine failure" -They were not thought to be contagious.
This is why a theater employee of 22 years fully immunized in New York who developed measles in 2011 was released without hospitalization or quarantine. But as Typhoid Mary, this patient was found to be unintentionally contagious. Ultimately, it transmitted measles to four others, according to a recent report Clinical Infectious Diseases ensuing symptoms in the 88 persons with whom "Measles Mary" interacted while she was sick . Surprisingly, two secondary patients had been fully vaccinated. And while the other two had no record of receiving the vaccine, they both showed signs of prior exposure to measles which would have given immunity.
Further examination of blood samples taken during treatment revealed how the immune Mary measles broke down. As a first line of defense against measles and other microbes, humans rely on a natural spur of IgM antibodies. As a wooden shield, they offer some protection against microbial attacks, but are not impenetrable. The vaccine (or the measles) prompts the body to complete the primary buffer with a stronger armor IgG antibodies, some of which are able to neutralize the measles virus so can not enter cells or spread to other patients. This secondary immune response is presumed to last for decades.
By analyzing his blood, the researchers found that Mary measles IgM mounted a defense, as if she had never been vaccinated. His blood also contained a powerful arsenal of IgG antibodies, but a review revealed that none of these IgG antibodies were actually able to neutralize the measles virus. It seemed that his immunity given vaccine had decreased.
While officials of Public Health assumed that immunity against measles still hard, the case of Mary measles highlights the fact that "the actual length [of immunity] after infection or vaccination is not clear, "said Jennifer Rosen, who conducted the survey as director of epidemiology and surveillance at the New York City Office of immunization. The possibility of decreased immunity is particularly worrying that the virus surfaces in major US hubs such as Boston, Seattle, New York, and the Los Angeles area. Rosen does not believe this one case merit a change in the vaccination such strategy, give adults booster shots, but she said the more regular monitoring to assess the strength of measles immunity people is justified.
If it turns that vaccinated people lose their immunity as they age, which could expose them to measles outbreaks seeded by persons who are unvaccinated increasingly common in the United States and other developed countries. Even a vaccine failure rate of 3% to 5% could devastate a school with several thousand students, said Robert Jacobson, director of clinical research for a vaccine against the Mayo Clinic Research Group in Rochester, Minnesota, who was not involved in the study. Still, he said, "vaccine failure" The biggest thing with measles happens when people refuse the vaccine first. "
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