The vaccine-derived poliovirus that left an unvaccinated US resident with the country’s first case of paralytic polio in nearly a decade has been genetically linked to its spread in two other countries: the UK and Israel. Now that it has been detected in the United States, health officials fear it has spread to hundreds or even thousands of people in a poorly vaccinated New York county.
On Monday, New York officials urged unvaccinated residents to get vaccinated “as soon as possible” to prevent further spread of the virus.
“Polio is highly contagious and an individual can transmit the virus even if they are not sick,” the New York State Department of Health said in a news release today. The virus spreads easily through the faecal-oral route due to poor hygiene and sanitation. The virus is transmitted by direct contact with an infected person or contaminated food or water. “Symptoms, which can be mild and flu-like, can take up to 30 days to appear, during which time an infected person can transmit the virus to others,” the health department added.
About one in 200 people infected with poliovirus develop paralysis, according to the US Centers for Disease Control and Prevention. This means that for the single case of paralytic polio in New York – which was not linked to any international travel – hundreds of others were likely already infected.
Pockets of risk
Most Americans have been vaccinated against the poliovirus, which protects them from the dangerous virus. The three-dose inactivated polio vaccine (IPV), given in the first 24 months with a fourth booster dose between ages 4 and 6, is part of the CDC’s standard immunization schedule. According to 2015 CDC data, nearly 93% of American children have received their three doses of IPV by age 2.
But, the New York paralytic polio case was discovered in Rockland County, a northern suburb of New York, which has pockets of low vaccination rates. In fact, in 2019 the county was plagued with an explosive outbreak of measles due to the same issue.
According to the state health department, Rockland County currently has a polio vaccination rate of just 60.5 percent among 2-year-olds, compared to a statewide average of 79 percent. State.
The paralytic case in Rockland, which occurred in an unvaccinated young adult, was first reported by authorities on July 21, but the person’s symptoms began in June. Since then, transmission has probably continued, with epidemiologists now say thousands could be infected.
And that’s just in the United States. On Friday, the Global Polio Eradication Initiative (GPEI) announced that the strain of vaccine-derived poliovirus that caused Rockland’s case – a type 2 VDPV – is genetically related to viruses detected in sewage sampling in London and Jerusalem, suggesting sustained multinational spread. dangerous virus.
To be clear, vaccine-derived poliovirus strains evolve from oral polio vaccines (OPV), which are no longer used in the US or UK. (Israel uses both IPV and OPV.) Oral polio vaccines use weakened viruses which, if able to spread from person to person in a setting of poor sanitation and low rates vaccination, can mutate to regain pathogenic capacities. It is not known where and how this VDPV2 originated and spread.
“It is vital that all countries, especially those with a high volume of travel and contact with polio-affected countries and areas, strengthen surveillance to rapidly detect any new virus importation and facilitate a response. fast,” said the GPEI. “Countries, territories and areas should also maintain uniformly high routine immunization coverage at the district and lowest administrative level to protect children against poliomyelitis and minimize the consequences of the introduction of any new virus.”
New York officials are heeding that call, opening vaccination clinics and urging residents to line up for vaccines, especially children.
“Polio is a dangerous disease with potentially devastating consequences,” New York State Health Commissioner Mary Bassett said in a statement. “In the United States, we are so fortunate to have the crucial protection afforded by polio vaccination, which has protected our country and New Yorkers for more than 60 years. Given how quickly polio can spread, now is the time for every adult, parent, and guardian to get themselves and their children vaccinated as soon as possible.”