A specific type of poliovirus is spreading in Rockland County, New York, as well as neighboring areas, prompting the World Health Organization (WHO) to link the United States. list of countries (opens in new tab) Where similar polioviruses have been found. The list includes about 30 countries in Europe, Asia and Africa such as the United Kingdom, Israel, Yemen, Algeria and Niger.
America’s official inclusion in this list was announced last week by U.S. Centers for Disease Control and Prevention (opens in new tab) (CDC) and the news raised questions about what happens next. Do people who received a full dose of polio vaccine as a child need a booster now? What should you do if you are unsure about your vaccination status, or if you know for sure that you have not received the polio vaccine?
Importantly, there is no comprehensive recommendation for fully vaccinated people to take a polio booster.
“Certainly, at this time, there are no national or local recommendations for people who are safe about their childhood vaccination series need additional boosters,” Dr. William Schaffner, professor of medicine in the division of infectious diseases at Vanderbilt University School of Medicine in Tennessee. However, he notes that there may be select circumstances — which we’ll detail below — in which it may be appropriate for a person to seek a booster.
related: Who made the polio vaccine?
For now, health officials’ primary concern is vaccinating people who have not yet completed their polio vaccination series, Schaffner told Live Science.
“Polio vaccination is the safest and best way to fight this debilitating disease, and it is essential that people in these communities are immediately updated on polio vaccination,” said Dr. Jose R. Romero, director of the CDC’s National Center. For vaccination and respiratory diseases, the CDC statement said. “We cannot stress enough that polio is a dangerous disease with no cure.”
Baseline Polio Vaccine Recommendations
Since 2000, the US has used only inactivated polio vaccine (IPV), a shot that is usually injected into the arm or leg and contains “dead” poliovirus that cannot cause disease. . CDC (opens in new tab), Another type of polio vaccine, the oral polio vaccine (OPV), is equally effective, but its use was stopped in the US because it contains live, but weakened, poliovirus. Live Science previously reported, this weak virus Can be shed in the feces of vaccinated people and, in rare instances, can evolve to behave like wild, naturally occurring polioviruses capable of causing disease and potentially paralysis in non-vaccinated people It is possible
Because of this risk, the US now only administers IPV, but “vaccine-derived” polioviruses can still potentially be imported from places that use OPVs – and that is exactly what has happened in the current outbreak.
“This shows how vulnerable we are to imports — not just poliovirus, but other viruses, germs, from overseas,” Schaffner said.
To protect against polio, the CDC recommends four doses of IPV for US children, with one dose at each of the following ages: 2 months of age, 4 months of age, 6 to 18 months of age middle and between 4 and 6 years of age. , CDC also offers many “Catch-Up Schedule” (opens in new tab) For children who start their vaccination series late or have a delay between doses.
Adults who have never been vaccinated against polio should receive three doses of IPV. These individuals can receive their first dose anytime, a second dose one to two months later, and a third dose six to 12 months after that, the CDC recommends. Adults who have received only one or two doses in the past should take additional doses to reach the recommended three.
Most US residents complete their polio vaccine series in childhood and getting a booster until later in life is generally not recommended. “This is evidence of the very solid, lifelong protection you get from the polio vaccine,” Schaffner said.
The first polio vaccine became available in 1955 and shots have been recommended as routine vaccination since then. as per verification (opens in new tab), An adult is considered fully vaccinated if he has received at least three doses of IPV or “trivalent” OPV (TOPV), which means OPV that protects against all three types of poliovirus, P1, P2 and P3. Is. Alternatively, an adult is fully vaccinated if he has received four doses of any combination of IPV and TOPV, CDC (opens in new tab),
Two doses of IPV are at least 90% protective against paralytic polio, which can occur when the virus infiltrates the central nervous system and causes weakness or paralysis in the arms, legs, or both; This can lead to permanent disability and death. According to the CDC, the three doses are at least 99% protective.
Who needs a polio booster?
There are instances in which fully vaccinated adults may consider a one-time polio booster.
For example, a booster will be recommended if you work in a laboratory or health care setting where you handle poliovirus samples, or if you are a health care worker treating patients with polio or the virus. Can interact with close contacts of infected people. , If you are traveling to a country where your risk of exposure to polio is “high,” you may want to look for a booster. For example, wild poliovirus still circulates in Afghanistan and Pakistan, and long-term visitors should get an IPV booster between four weeks and a year before traveling there. Global Polio Eradication Initiative (opens in new tab), (No similar recommendations have yet been made for the US.)
So far, only one case of paralytic polio has been detected in the US outbreak; This occurred in an unvaccinated adult in Rockland County. Subsequently, poliovirus was detected in wastewater samples from Rockland County, Orange County, Sullivan County, New York City, and Nassau County. New York State Department of Health reported (opens in new tab),
The Department of Health currently recommends polio boosters for the following New Yorkers:
- Persons who may or may have close contact with a person infected or suspected of poliovirus or with household members or other close contacts of such person.
- Health care providers who work in areas where poliovirus has been detected and can handle samples that may contain poliovirus or who treat patients who may have polio.
- Persons with occupational exposure to wastewater.
People from affected countries who have become vulnerable Defence system Might also consider a booster, said Vincent Raniello, a poliovirus specialist at Columbia University Vagelos College of Physicians and Surgeons. Statement (opens in new tab), And if you’re not sure how many doses of polio vaccine you’ve received, you might also consider increasing it, he said.
There are some antibody tests for polio, but these are not recommended to assess vaccination status because, as of 2017, there is limited access to tests that screen for antibodies against all three types of poliovirus. Morbidity and Mortality Weekly Report (opens in new tab) Published by CDC. “In the absence of availability of testing for antibodies for all 3 serotypes, serological testing to assess immunity is not recommended,” the report said.
For US residents beyond New York, the risk of exposure to polio is likely to be the same as before the outbreak, Schaffner said — that is, negligible. However, people exposed to the virus in New York could potentially board a plane and carry polio to additional locations; For this reason, vaccination remains important no matter where you live, he said.
It’s also important to note that “while IPV is great at preventing the most serious potential effects of the disease, people who receive the vaccine can still be carriers of polio and transmit it to others,” Dr. Lena Wayne, an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health. CNN (opens in new tab),
Those vaccinated with IPV can still pass poliovirus in their feces if they ever come into contact with the pathogen, even if they are protected from paralysis, according to this, pan american health organization (opens in new tab), This is because IPV is a very strong Antibodies Reaction in the blood but not as effective in generating immunity in the intestines.
Polio virus is often spread through contact with the feces of an infected person; Less commonly, it can be transmitted through respiratory droplets released when an infected person sneezes or coughs, according to CDC (opens in new tab), Frequent hand washing with soap and water can help prevent the spread of the virus; Notably, however, alcohol-based hand sanitizers do not kill poliovirus.
Most people who catch polio do not show any symptoms. About 25% develop flu-like symptoms, including sore throat, fever, fatigue, abdominal pain, and nausea. A very small fraction of infected people develop severe symptoms, such as meningitis, an infection of the spinal cord and/or tissue surrounding the brain; or paralysis, which can lead to permanent disability and death.
Sometimes, people who recover from polio develop new muscle pain, weakness, or paralysis decades later; This is known as post-polio syndrome.
Originally published on Live Science.