Dear Doctor: I heard about a polio outbreak in Nigeria this summer. Might there be an outbreak here in the United States?
Dear Reader: Polio is a crippling, and sometimes fatal, infectious disease that was once common in the U.S. Caused by the polio virus, the disease was widespread among children. During the 1940s and '50s, outbreaks caused spinal and respiratory paralysis in 15,000 sufferers each year. With potentially dire outcomes and no cure, polio became one of the most feared childhood diseases in the United States.
That changed thanks to the development of the polio vaccine in the mid-1950s, and to the success of our ongoing national vaccination program. The Centers for Disease Control and Prevention states that polio has been eliminated in the U.S.
In our country, vaccination programs have resulted in a sharp decline in the number of polio cases, from 35,000 in 1953 to 5,300 four years later. With the introduction of an oral vaccine in 1961, the number of new cases acquired in the U.S. continued to plummet. There have been no new cases of polio reported in the U.S. since 1979. The last known case of polio acquired outside the U.S. and imported into the country was in 1993.
However, as you point out, polio remains a global concern. International health organizations have made polio vaccination a priority, with more than 2.5 billion children vaccinated worldwide since 1988. As a result, the overall number of new polio cases worldwide has dropped a remarkable 99 percent.
In 10 countries, however, including Afghanistan, Syria and Pakistan, vaccination programs have been difficult to implement and the disease continues to spread. And though Nigeria was declared polio-free in 2014, two new cases last August and a third case in September have raised the alarm. World health organizations are now redoubling their efforts to implement ongoing vaccination programs.
Is this polio epidemic a danger to the U.S.? The answer is no. Vaccination rates among adults are extremely high, and as long as parents continue to be vigilant about vaccinations and boosters for their children, we as a nation will remain immune to this terrible disease.
According to CDC guidelines, children should be vaccinated with inactivated polio vaccine (IPV) four times -- at 2 months of age, at 4 months of age, a dose between 6 and 18 months of age, and a booster dose between 4 and 6 years of age. Until this vaccination schedule is complete, children should not travel to an area where polio is still an active infection.
Eradicating polio worldwide has been one of the most remarkable and successful international health initiatives. Its ongoing success depends on each one of us continuing to be vigilant about vaccination.
(Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and primary care physician at UCLA Health.)