A young man affected by paralysis caused by the polio virus was admitted to hospital in New York on 21 July. This is the first polio case recorded in the USA since 2013. The authorities are trying to identify the source of the infection and are calling on the non-immunized population to be vaccinated.
Polio, which is caused by an ancient viral virus, mainly affects children under 5. In 95% of cases, individuals develop no symptoms. However, in rare cases when symptoms do appear, they can take different forms including a sore throat, headache, diarrhea, nausea, fatigue, and fever. One in 200 of those patients infected can develop paralysis and the mortality rate amongst those with paralysis is around 5% to 10%.
First polio case since 2013
The New York Department of Health has confirmed the case of polio in a young man from New York’s Rockland County. The authorities assume that the virus probably originated from an oral vaccine that has not been used in the USA since 2000 so, therefore, do not rule out that the virus could have been brought into the country from overseas.
While the patient can already be considered to be non-contagious, the authorities have taken action to detect the source of the infection. Currently, the state is checking sewage systems for any sign of the virus and taking samples for testing. No other cases have been registered at the present time but officials are calling for the public to be vaccinated if they are not already immunized. State Health Commissioner Dr. Mary T. Bassett in her statement said:
“The polio vaccine is safe and effective, protecting against this potentially debilitating disease, and it has been part of the backbone of required, routine childhood immunizations recommended by health officials and public health agencies nationwide.”
Vaccination as only anti-polio solution
Although medicines can alleviate the symptoms of the disease, there is no treatment for polio. To fight the infection, countries have been effectively using two kinds of vaccines – the oral vaccine taken by mouth which contains a weakened form of the virus, and the inactivated poliovirus vaccine which is injected.
The oral form of the vaccine is cheaper and has played a crucial role in eliminating the disease, especially in low- and middle-income countries. Dr. John Brownstein, an epidemiologist at Boston Children’s Hospital and an ABC News contributor, said:
“It’s a live attenuated virus. It’s a weakened virus that provides really good immunity in the gut, where the virus replicates, and it sheds in stool, which can spread through sewage and help protect the community.”
However, the oral vaccine also has an adverse effect as, in rare cases, it can cause vaccine-derived poliovirus. The infection could then spread through the sewage system and affect the unvaccinated so, in view of this risk, the US abandoned the oral vaccine in 2000. Wild polio, in contrast, circulates naturally in the environment.
Since the first vaccine was introduced in 1955, the world has successfully fought the virus. Wild poliovirus cases have dropped by around 99% since 1988. In 2021, the number of cases recorded reached six compared to 350,000 cases in 1988. Today, the countries of concern are Pakistan and Afghanistan as the wild form of the virus still circulates in these endemic countries. Cases of infection are also registered in outbreak countries including those in Africa, the Eastern Mediterranean, and Europe.
Fig.1.Number of cases of the poliovirus now
Source: Polio Eradication