I've been getting a lot of questions from people about what they need to do to prevent polio. Especially: do we need to get a polio vaccine booster? Let's discuss!
What is Polio?:
Poliomyelitis (polio) is a potentially disabling and life threatening disease caused by an infection of poliovirus progressing into the spinal cord and causing paralysis.
Most people infected with poliovirus will not experience any visible symptoms. 25% Of people infected will experience flu like symptoms for 2-5 days (sore throat, fever, fatigue, sore throat, headache, nausea).
Between 1-5% of all people infected with poliovirus will develop cases of meningitis (an infection of the covering of the spinal cord and/or brain) and these can lead to polio disease. Paralysis (mostly presenting as weakness in the limbs) occurs in less than 1% of people with poliovirus. Paralysis is the most severe symptom associated with poliovirus because it can lead to permanent disability and death. Between 2-10% of people who have paralysis from poliovirus infection die, because the virus affects the muscles that help them breathe.
Poliovirus illnesses can re emerge in adulthood after many years with more serious symptoms the second time.
History:
Before a polio vaccine was available there were several polio epidemics between 1948-1955. People avoided gatherings and many parents would not allow their children to play with new friends out of caution. Patients with polio were treated in isolation wards and many patients with paralysis utilized iron lungs (negative pressure ventilators) to help them breathe so they could live longer.
Before vaccination was introduced, polio outbreaks caused more than 15,000 cases of paralysis each year. Following introduction of vaccines the number of polio cases fell rapidly to less than 100 in the 1960s and fewer than 10 in the 1970s.
Graph: cdc.gov
So....why are we talking about Polio now?
The first case of polio paralysis in decades was discovered in Rockland County, New York in July, 2021. A 20-year-old unvaccinated young man presented with signs of paralysis and was determined to have poliomyelitis. Rockland County, NY is an area with known vaccine resistance: statewide the childhood vaccination rate for polio vaccination is about 80%, but in Rockland County it is only 60%.
The fact that we are seeing a polio paralysis case at all is concerning, and is an indication that there has likely been community transmission. As stated above, paralysis will only happen to less than 1% of poliovirus cases.
Weeks after the polio case was discovered in Rockland County, there were also news reports of poliovirus being found during wastewater surveillance in New York City. There had already been reports in June that poliovirus was detected in wastewater in the UK. The fact that we are seeing poliovirus in wastewater is another confirmation that there has been community transmission of poliovirus.
**It's important to note that the presence of polio virus in the wastewater does not mean there is poliovirus in drinking water.
Transmission:
Poliovirus is highly contagious and spreads from person to person via contact with feces and sometimes via respiratory droplets from sneezing. It is possible to get polio from touching something, picking up minute pieces of feces on the hands, and touching the mouth. People can also get it from putting contaminated items into their mouth objects like toys or food.
What should we do?:
The case of Polio in Rockland County and the wastewater findings do not change current CDC recommendations for polio vaccination. CDC urges everyone who is not fully vaccinated to complete the polio vaccination series as soon as possible. The inactivated poliovirus vaccine (IPV) is 99% effective at preventing polio in fully vaccinated people.
The reason for the public health alerts about vaccination is because many children fell behind on vaccination during the COVID-19 pandemic, so it is vital that parents bring their children as soon as possible to get caught up on their vaccines. Getting children vaccinated with IPV will protect them against both poliovirus and severe poliomyelitis.
CDC recommends that children get four doses of the IPV vaccine at the following ages:
2 months
4 months
6-18 months, and
4-6 years.
Most adults are most likely already vaccinated against polio, but if an adult is unvaccinated they can receive the three-dose catch-up schedule:
The first dose at any time
The second dose 1 to 2 months later
The third dose 6 to 12 months after the second
Now I'll finally answer the question about polio boosters:
Boosters are not being recommended at this time for the majority of people. There is no evidence to support their use in fully vaccinated adults.
Adults can get a one-time lifetime booster if they are in the following groups: travelers to areas where polio is endemic, laboratory and healthcare workers who handle specimens, healthcare workers who are treating patients who could have polio, people who are in contact with or caring for a person infected with polio, unvaccinated adults whose children received an oral poliovirus vaccine (for example, international adoptees or refugees).
If this guidance changes at all, of course I will let you know.