A new study from researchers at the University of Rochester School of Medicine and Dentistry strongly supports vaccinating individuals against bird flu viruses before a possible pandemic. Scientists found that individuals who received a vaccine against the H5N1 bird flu virus didn’t produce much of an immune response at first, but when they were vaccinated a second time their bodies produced an army of T-helper cells – a type of white blood cell that fights infection. The findings, published in the Journal of Infectious Diseases, suggest that priming the body ahead of a possible pandemic is a smart move.
Researchers, led by Jennifer Nayak, M.D., assistant professor of Pediatrics and Andrea Sant, Ph.D., professor of Microbiology and Immunology, compared pre- and post-vaccination levels of T-helper cells in people previously enrolled in trials of H5N1 vaccines to individuals with no past exposure to bird flu viruses. Vaccination induced barely detectable levels of T-helper cells in those with no past exposure, but robust levels in those being vaccinated for the second time. Higher levels of T-helper cells upped the production of antibodies – proteins that target and eliminate intruders like viruses.
There have been ongoing infections with the H5N1 bird flu virus since 1997 and research shows that only a small number of mutations are needed for the virus to gain the ability to spread from person to person. In a pandemic, when time is of the essence, anything that will shorten the time to protection – like giving one vaccine instead of two – will significantly limit a pandemic’s spread.
The research project was conducted as part of the New York Influenza Center of Excellence, which is based at UR and funded by the National Institutes of Health. In addition to Nayak and Sant, the research team consisted of Katherine Richards, David H. Smith Center for Vaccine Biology and Immunology, Hongmei Yang, research assistant professor of Biostatistics and Computational Biology and John Treanor, professor and chief of Infectious Diseases.