What you should know about the polio vaccine

What you should know about the polio vaccine

Thanks to the invention of an effective vaccine and the successful vaccination campaign that followed, the US (and much of the rest of the world) has been polio-free for decades. So, when a case of poliomyelitis with paralysis confirmed in an unvaccinated person in New York in July, the alarm went off. More sewage testing found polio in more New York counties, indicating local community spread. In September, New York declared disaster to increase the reach of the vaccine. Health officials everywhere are reminding people to vaccinate their children against polio, which can cause paralysis and be deadly.

There are two types of polio vaccines: inactivated polio vaccines, which have not been available in the US in more than 20 years, and oral polio vaccines, which are still given in other countries and are especially effective in places where there are outbreaks. Due to the spread of polio in New York (which is related to the strain also found in UK and Israel), health officials could return to introduce an oral polio vaccine, albeit a newer version of it. A panel that makes recommendations to the US Centers for Disease Control and Prevention met last week to discuss both types of polio vaccines as a way “to proactively stay prepared,” a spokesman said. from the CDC. The newer oral polio vaccine (nOPV2) has not yet been licensed or recommended.

“It’s going to be a process. It’s not something that we can pull the trigger and make happen overnight,” said Dr. Janell Routh, CDC lead for domestic polio. he told CNBC on Friday. “There will be a lot of thought and discussion about reintroducing an oral polio vaccine in the United States.”

Compared to the inactivated polio vaccine now offered in the US, the oral polio vaccine has some advantages, including ease of administration and the ability to stop the transmission of the virus from person to person. But it also has some drawbacks, including the potential to mutate into a contagious form of the virus and, in very rare cases, cause paralysis in unvaccinated people. It’s a vaccine-derived strain of polio circulating in New York, which is believed to have originated in another country that uses oral polio vaccines.

While the vaccines we now get in the US are effective against polio, oral vaccines can further limit the spread of polio, according to shared information at a CDC advisory committee meeting. If polio spreads beyond where it circulates locally, the hope is that the introduction of another tool will help us better respond to an outbreak.

But we are not there now. Ross Kedl, an immunologist and professor at the University of Colorado Anschutz School of Medicine, told CNET in September that polio is not much of a threat to the US right now, at least for those who have been vaccinated. against her. Most of us received all our vaccinations as children and it is a requirement to attend most schools.

“Where it does cause problems is in communities where uptake of the vaccine is lower than necessary,” Kedl said.

In communities where vaccination rates are lower than normal, such as Rockland County, where polio was reported in the US, the virus may once again become a problem. On 60% of children who live in Rockland County have been vaccinated against polio before their second birthday, according to information from the state health department. Comparatively, the CDC reports that about 92% of 2-year-olds nationwide have been vaccinated against polio.

Polio vaccination has largely avoided the politicization and disinformation campaigns of other vaccines, Kedl says, in part because the devastation, paralysis and death the disease caused in the 1940s are still fresh in memory. of people. And much of that damage was done to children.

“When you start to focus on children, people sit up and take notice,” Kedl said.

Here’s what we know about polio vaccination.

A little girl gets a shot in her upper arm.

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What types of polio vaccines are there?

There are two types of polio vaccine. The inactivated injectable vaccine is the only one distributed in the US since 2000, and it is recommended as a series of four injections that are usually given before the age of 6 years. The CDC recommends the first injection at 2 months. The oral vaccine (also called the Sabin vaccine), which contains a weakened or attenuated live virus, is administered orally.

The oral vaccine is given in other countries, and the current spread in New York is linked to a vaccine-derived virus that has also been detected in the UK and Israel. in a statementthe CDC said these viruses are not caused by children receiving the polio vaccine.

Dr. Amesh Adalja is an infectious disease physician and senior scholar at the Johns Hopkins Center for Health Security. He says the oral polio vaccine is still given in other countries because it’s cheaper and easier to administer (no needles needed), but it also “provides much stronger immunity.”

“The Sabin vaccine was used in the US for some time, but as polio risks decreased, the Salk (injectable) vaccine became the favorite,” Adalja said in an email.

According to Kedl, the oral polio vaccine is so effective against infection because it stops the virus where it starts: the gut. Polio enters the body through the mouth, usually through hands contaminated by the feces of an infected person, and immunity in the intestines prevents the virus from reaching the nerves. This is a similar reason why some researchers say that a COVID-19 nasal vaccine it will be more effective in preventing infection, because the respiratory virus enters through the nose or upper respiratory tract.

But while highly effective against polio, live vaccines carry the risk of the weakened virus mutating into more contagious forms.

“Polio is the symbol of why attenuated vaccines are so good, and why we should also always develop a more subunit or killed vaccine approach,” Kedl said.

A child receives an oral polio vaccine

Oral polio vaccines are no longer available in the US, but they remain an important part of polio eradication efforts in other countries.

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How effective is the polio vaccine?

The CDC says that three doses of IPV (the inactive injections currently available in the US) are at least 99% effective in preventing paralysis caused by poliomyelitis, and that two doses are 90% effective. Even for a vaccine that helped eradicate a disease, that seems really high. But while the vaccines haven’t been fully tested in the US in decades, that effectiveness rings true with Kedl.

“It’s definitely one of the most successful vaccines, in any form, that’s ever been done,” Kedl said. “Not because the vaccines themselves are high-tech and fantastic, it’s just that polio itself is really susceptible to a fairly moderate immune response.” That is, we may need fewer antibodies produced by the vaccine to protect us against polio compared to other viruses.

“Polio seems very likely to be eliminated by a reasonably modest vaccine response,” he noted. “Thanks god.”

Do I need another polio vaccine or booster?

With only local spread in New York, the CDC has not made any changes to its vaccine recommendations for the general public at this time.

“The CDC really only recommends boosters in special circumstances, including travel to areas where there is wild polio or where vaccine-derived strains are circulating,” Adalja said. “New York State has expanded that recommendation to include healthcare workers and wastewater workers.” Other people, including some child care workers in areas of New York with community transmission, or people who might be at higher risk of coming into contact with someone with polio, can also get a booster.

Health officials in New York are urging everyone to start their polio vaccine series as soon as possible if they haven’t already, including adults who have never been vaccinated or don’t recall being vaccinated. If you live anywhere in the US and have not been vaccinated against polio, contact your doctor.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health care provider regarding any questions you may have about a medical condition or health goals.

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