The most recent cases of poliomyelitis due to an importation of wild polio type 1 occurred in unvaccinated Bulgarian children [ 1].
However, in countries where polio has already been eradicated, and in the years following global polio eradication, the risk of vaccine-associated paralytic polio and of polio outbreaks due to circulating vaccine-derived polioviruses means that continued use of OPV is untenable.
Stopping polio in India will prevent a recurrence of the polio outbreaks – due to virus of Indian origin – seen in recent years in countries as diverse as Angola, Bangladesh, Nepal, Tajikistan, and Russia.
Reduction in polio cases "Over the last 20 years, there has been a 99 per cent reduction in polio cases due to the commitment of Rotary and other partners in the Global Polio Eradication Initiative," said UNICEF Executive Director Ann M. Veneman.
Overall, 5 10% of patients with paralytic polio die due to the paralysis of muscles used for breathing.
As the incidence of wild polio diminishes, nations transition from use of the oral vaccine back to the injected vaccine because the direct risk of iatrogenic polio (VAPP) due to OPV outweighs the indirect benefit of immunization via subclinical transmission of OPV.
Polio outbreaks due to circulating vaccine-derived polioviruses (cVDPV) are rare, but possible.
In the 2002-2003 period, for the first time in history, more countries suffered polio cases due to importations than were themselves endemic for the disease.
"You would not be able to invent the polio vaccine today," due to FDA regulations, Thiel said.
However, none of the synthesized nucleosides exhibited antiviral activities against RNA viruses including coxsakie, influenza, corona and polio viruses, maybe due to their 2′,3′-dideoxy structure.
