Adult antibody thresholds misidentify immunocompromised children’s immunity

Immunocompromised children may not be properly protected from measles, according to a new study. Current methods use adult antibody levels to decide if these children need a booster shot for the measles, mumps, and rubella (MMR) vaccine. However, this approach misses many children who actually require revaccination. The study, published in Clinical Chemistry, highlights the need for better protection as measles cases rise again in the U.S. After being declared eliminated in the early 2000s, incidents of measles have increased significantly. Falling vaccination rates and vaccine skepticism are contributing factors to this surge. Immunocompromised individuals are particularly vulnerable since vaccines tend to be less effective for them. Typically, herd immunity helps protect those who cannot be vaccinated. However, as herd immunity for measles declines, it's crucial for immunocompromised individuals to understand their immune status and seek boosters when necessary. The researchers, led by Dr. Sarah Wheeler from the University of Pittsburgh Medical Center, analyzed blood samples from healthy children and those with autoimmune diseases. They found that children had higher antibody levels than adults after vaccination. About 25% of children in the study would have been wrongly deemed immune if only adult antibody levels were used. This indicates that specific antibody thresholds for children should be established for accurate immunity assessments. Wheeler believes that these changes will enhance the evaluation and delivery of necessary vaccinations for at-risk children. Future research could also explore similar guidelines for other vaccines.