A specific type of poliovirus has spread in Rockland County, New York, and surrounding areas, prompting the World Health Organization (WHO) to add the United States to a list of countries (opens in a new tab) where similar polioviruses have been detected. The list includes around 30 countries from Europe, Asia and Africa, such as the UK, Israel, Yemen, Algeria and Niger.
The official addition of the United States to this list was announced last week by the US Centers for Disease Control and Prevention (opens in a new tab) (CDC) and the news has raised questions about what happens next. Do people who received all their childhood polio vaccine doses now need a booster? What if you are unsure of your vaccination status or know for sure that you have not received the polio vaccine?
Crucially, there is no sweeping recommendation for fully vaccinated people to seek polio boosters.
“Certainly, at this time, there have been no national or local recommendations that people who are sure of their round of childhood vaccinations need an additional booster,” said Dr. William Schaffner, professor of medicine at the division of infectious diseases. at Vanderbilt University School of Medicine in Tennessee. However, he noted that there may be certain circumstances – which we’ll detail below – in which it might be reasonable for someone to request a callback.
Related: Who created the polio vaccine?
For now, the main concern of health officials is to vaccinate those who have not yet completed their series of polio vaccinations, Schaffner told Live Science.
“Vaccination against polio is the safest and best way to fight this debilitating disease and it is imperative that people in these communities who are unvaccinated get up to date with polio vaccination immediately,” said said Dr. José R. Romero, director of the CDC’s National Center. for vaccination and respiratory diseases, said in the CDC statement. “We cannot stress enough that polio is a dangerous disease for which there is no cure.”
Basic polio vaccine recommendations
According to CDC (opens in a new tab). Another type of polio vaccine, oral polio vaccine (OPV), is equally effective, but its use has been discontinued in the United States because it contains live, but weakened, poliovirus. Previously reported Live Science. These weakened virus can be excreted in the feces of vaccinated people and, in rare cases, can evolve to behave like naturally occurring wild polioviruses capable of causing disease and potentially paralysis in unvaccinated people.
Because of this risk, the US now only administers IPV, but ‘vaccine-derived’ polioviruses can still potentially be imported from places that use OPV – and that’s exactly what happened. during the current epidemic.
“It reveals how vulnerable we are to imports — not just poliovirus, but other viruses, germs, from abroad,” Schaffner said.
To guard against polio, the CDC recommends that children in the United States receive four doses of IPV, with one dose given at each of the following ages: 2 months, 4 months, 6 to 18 months, and 4 to 6 years. . The CDC also offers several “catch-up hours” (opens in a new tab) for children who start their vaccination series late or who are delayed between doses.
Adults who have never received a polio vaccine should receive three doses of IPV. These people can receive their first dose at any time, receive the second dose one to two months later, and receive the third dose six to 12 months later, the CDC recommends. Adults who have only received one or two doses in the past should seek additional doses to reach the recommended three doses.
Most US residents complete their series of polio vaccines in childhood and getting boosters later in life is generally not recommended. “This is just a testament to the very strong, lifelong protection you get from the polio vaccine,” Schaffner said.
The first polio vaccines became available in 1955 and injections have been recommended as routine vaccinations ever since. according to Check (opens in a new tab). An adult is considered fully immunized if they have received at least three doses of IPV or “trivalent” OPV (tOPV), i.e. OPV that protects against all three types of poliovirus, P1, P2 and P3. Alternatively, an adult is fully immunized if they have received four doses of any combination of IPV and tOPV, depending on the CDC (opens in a new tab).
Two doses of IPV provide at least 90% protection against paralytic poliomyelitis, 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. Three doses are at least 99% protective, according to the CDC.
Related: Africa declared free of wild poliovirus
Who needs a polio booster?
There are instances where fully immunized adults may consider a one-time polio booster.
For example, a booster would be recommended if you work in a laboratory or healthcare facility where you handle poliovirus specimens, or if you are a healthcare worker who treats polio patients or who may interact with contacts ties of people infected with the virus. You can also request a booster if you are traveling to a country with a “higher” risk of polio exposure. For example, wild poliovirus is still circulating in Afghanistan and Pakistan, and long-term visitors should receive an IPV booster between four weeks and a year before traveling there, according to the Global Polio Eradication Initiative (opens in a new tab). (A similar recommendation has yet to be extended to the United States.)
So far, only one case of paralytic poliomyelitis has been detected in the outbreak in the United States; this occurred in an unvaccinated adult in Rockland County. Subsequently, poliovirus was detected in sewage samples from Rockland County, Orange County, Sullivan County, New York, and Nassau County, the New York State Department of Health reported (opens in a new tab).
The Health Department currently recommends polio boosters for the following New Yorkers:
- People who will or may have close contact with someone known or suspected to be infected with poliovirus or that person’s household members or other close contacts.
- Health care providers who work in areas where poliovirus has been detected and who may handle specimens that may contain poliovirus or who treat patients who may have polio.
- People occupationally exposed to wastewater.
Residents of affected counties who have weakened immune systems could also consider a booster, Vincent Racaniello, a poliovirus expert at Columbia University Vagelos College of Physicians and Surgeons, said in a statement (opens in a new tab). And if you’re not sure how many doses of polio vaccine you’ve had, you can also consider getting a booster, he said.
There are antibody tests for polio, but these are not recommended for assessing vaccination status because access to tests that screen for antibodies against the three types of poliovirus is limited, according to a 2017 report. Morbidity and Mortality Weekly Report (opens in a new tab) published by the CDC. “In the absence of availability of tests for antibodies against the 3 serotypes, serological tests are no longer recommended for assessing immunity,” the report states.
For U.S. residents beyond New York, the risk of polio exposure is likely similar to before the outbreak, Schaffner said, that is, negligible. However, people exposed to the virus in New York could potentially hop on a plane and transport polio to other places; for this reason, vaccination remains important no matter where you live, he said.
It is also essential to note that “although IPV is very effective in preventing the most serious potential effects of the disease, people who have received the vaccine could still be carriers of poliomyelitis and could transmit it to others” , said Dr. Leana Wen, an emergency physician. and professor of health policy and management at George Washington University Milken Institute School of Public Health, said CNN (opens in a new tab).
According to Pan American Health Organization (opens in a new tab). This is because LPI generates a very strong antibody response in the blood, but is not as effective in generating immunity in the intestines.
Poliovirus is most often spread through contact with the feces of an infected person; less commonly, it can be transmitted through respiratory droplets that are released when an infected person sneezes or coughs, depending on the CDC (opens in a new tab). Washing hands frequently with soap and water can help prevent the spread of the virus; notably, however, alcohol-based hand sanitizers do not kill polioviruses.
Most people who get poliomyelitis do not develop any noticeable symptoms. About 25% develop flu-like symptoms, including sore throat, fever, fatigue, stomach pain and nausea. A much smaller fraction of those infected develop serious symptoms, such as meningitis, an infection of the tissues surrounding the spinal cord and/or brain; or paralysis, which can lead to permanent disability and death.
Sometimes people who seem to recover from polio develop new muscle pain, weakness or paralysis decades later; this is called post-polio syndrome.
Originally posted on Live Science.
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