Children who have already received their oral polio vaccines (OPV) in recent years are not exempted from the national immunization days beginning tomorrow, Dayrit stressed.
The "Balik Patak Contra Polio" campaign, spearheaded by the Department of Health (DOH), intends to eradicate a mutated form of the wild polio virus.
A weakened strain of polio virus contained in polio vaccines administered to children worldwide in the 1990s had mutated into another strain as strong and lethal as the wild one, the DOH said.
"We are ready. We have more than enough vaccines to immunize the 12 million children aged 59 months and below that we are targeting," Dayrit said.
The immunization campaign will be house-to-house, where the DOH and local government health workers will be knocking on doors to administer the OPVs to children five years and below.
Apart from local government units, the DOH will be supported by the World Health Organization (WHO), the UNICEF, Rotary International, and other health organizations and LGUs.
"Our partners and we have already prepared 14.5 million anti-polio doses needed for the Feb. 2-8 round of the campaign," Dayrit said.
He added that some 21.5 million doses needed for the Mar. 2-8 leg of the campaign are already being prepared.
The government slated the anti-polio campaign after three cases of polio turned up in the country last year in Cagayan de Oro City and in Laguna and Cavite. Paralysis had already developed in two of the cases that all involved children.
While Dayrit said that the government had already addressed the problem with "mop-up" vaccinations in the three provinces where the virus turned up, the DOH is still conducting the nationwide drive to ensure the country keeps its "polio-free" status bestowed by the WHO in 2000.
Health officials however noted that with the three cases occurring in northern and southern islands, the mutated polio virus strain may have already spread in a wide area.
"The reason is the virus has mutated due to failure to maintain a high routine infant vaccination, which could then be traced to the fact that there had been an erratic supply of vaccines over the past two years," Dayrit said.
Dr. Sigrun Roesel of the WHO said that such a phenomenon of polio re-emerging from a polio-free country was rare, with a recurrence reported only in the Dominican Republic, Haiti and Egypt.
Roesel said the phenomenon was traced to the countries’ inconsistency in the administering of the yearly polio vaccination drives, resulting in low immunization rates.
Dayrit, for his part, admitted that the Philippines posted a low immunization rate last year, which he blamed on a shortage of vaccines and difficulty in reaching far-flung areas.