A new study by researchers from the University of Stanford depicts a painting of a close-filure where diseases, once eradicated in the country, could return realistically.
“At current state vaccination rates, measles can become endemic again,” wrote the authors when they have published their research this week in the Journal of the American Medical Association.
Generalized vaccination against measles led the declared virus eradicated to the United States in 2000. California has higher vaccination rates than the average. The last school year, 96.2% of state planters were vaccinated against measles, but it was slightly down compared to the previous year.
Ten years ago, Golden State maternal vaccinations hovered below 95% recommended to maintain the immunity of the herd. When a new, stricter law was adopted in 2015, a response to a Disneyland measles epidemic in 2014, vaccination rates reached just over 97%. But since then, rates have mainly dropped from year to year, concerning health officials.
“As vaccinations decrease, the effect will not be immediate,” said Mathew Kiang, assistant professor of epidemiology in Stanford and principal author, in an interview published by the University. “We wanted to know: when will we see the impact of decisions debated and taken now?”
The researchers used predictive models to see what a range of future scenarios might look like: what happens if the vaccination rates remain the same? What if they fall a little or fall a lot? How long could he take the most infectious diseases in the world to come back?
Their models suggest that current levels are likely to allow measles to return to endemicity in the United States over the next two decades, and faster if vaccination rates continue to drop. If the rates fall to half what they are now, the models suggest that there could be 51.2 million cases of measles in the country during a generation, 25 years. These infections, and other diseases such as rubella and polio which are likely to return under these models, could kill more than 150,000 people at that time.
Until this year, the United States had had no deaths of measles for more than a decade, but an epidemic of measles in progress in Texas resulted in the death of two children, both not vaccinated.
Including Kiang, four of the five authors are based in Stanford. Kate M. Bubar is a researcher with infectious diseases at Stanford Medicine, Yvonne Maldonado is a professor of pediatrics and infectious diseases, and Nathan C. LO is assistant professor of infectious diseases at university.
The authors have an eye on the current political climate around vaccines. “There are political debates in progress to reduce the calendar of infant vaccines, which can risk the re-emergence of infectious diseases previously eliminated,” they warn.
“With measles, we found that we are already on the precipice of the disaster,” said Kiang. “If the vaccination rates remain the same, the model predicts that measles can become endemic in about 20 years.”
Dogs would probably be the first disease eradicated to come back, because it is so contagious, but other diseases such as rubella, diphtheria and polio could also return if vaccination rates fall in half, depending on the model.
California Daily Newspapers
