Understandably, these events have sparked a lot of questions: Why does one case of polio worry officials? What does it mean to find poliovirus in wastewater? Who should be worried about contracting the disease? If someone had the vaccine years ago, are they still protected now?
CNN: So far, there has been only one documented case of paralysis due to poliovirus in New York. Why does one case worry health officials?
CNN: What does it mean that poliovirus has been detected in the wastewater of five counties, including New York City?
Wen: Finding poliovirus in sewage means one of two things: That there are people actively infected with polio who are shedding the virus, or that the virus signal could be from people who recently received the oral polio vaccine (OPV). OPV is no longer given in the United States — since 2000, the version used in the US is the inactivated polio vaccine (IPV), which is injected — but other countries are still using OPV, and it’s possible that travelers from those places are shedding virus from the vaccine.
In rare circumstances, the weakened virus from people who just received OPV could cause paralytic polio in unvaccinated individuals — which is a major reason why OPV is no longer used in the US.
CNN: How can people get polio?
CNN: Should New Yorkers be worried about contracting polio?
Wen: Again, people who are vaccinated against polio are extremely well-protected from paralytic polio, and should not be concerned at this point. It should be pointed out, however, that while IPV is very good at preventing the most severe potential effects of the disease, people who received the vaccine could still be carriers of polio and could transmit it to others. Those at risk for serious outcomes are people who are unvaccinated and those who are incompletely vaccinated, including young children under 6 who have not yet completed their polio vaccine series.
CNN: How many polio vaccines should someone receive?
Adults who have never been vaccinated against polio should receive three doses of IPV. The first should be given as soon as possible, the second one to two months after that and the third six to 12 months after the second.
CNN: If someone had the vaccine years ago, are they still protected? Who should get a polio booster now?
CNN: What if you’re not sure whether you were vaccinated? Say you don’t recall getting the vaccine, and it’s been many years. Is there a blood test you can take to verify either way?
Wen: You could check with your primary care physician’s office or state health department to see whether they have records of your immunizations. If they don’t, and there is no other way for you to verify — for example, by asking parents or other relatives or caregivers — you should speak with your health care provider about getting the full vaccine series for polio now. There is no blood test that can reliably detect whether you’re fully vaccinated against polio.
CNN: What if you or your family members haven’t yet gotten vaccinated against poliovirus?
Wen: People who have yet to receive any doses or are incompletely vaccinated should make sure to get their entire polio vaccine series right away. This is particularly important if they live in or around Rockland County in New York — but really everyone should get caught up with their routine immunizations.
It was a tragedy decades ago that so many children became permanently paralyzed and even died from polio. This should not happen again, since we have such effective vaccines that can prevent severe consequences of the disease.