New Delhi: Indians travelling to 17 nations where polio is making a troubling comeback could be advised to get vaccinated against the disease, ThePrint has learnt.
The 17 nations are Myanmar, China, Indonesia, Philippines, Papua New Guinea (PNG), Angola, Benin, Cameroon, Central African Republic, Chad, Côte d’Ivoire, Democratic Republic of the Congo, Ethiopia, Ghana, Togo, Zambia and Somalia.
In all these countries, the type of polio virus that can be seen is one derived from the vaccine.
The Ministry of Health and Family Welfare has been working on issuing advisories for the affected nations. The government is said to be especially concerned over the comeback of polio in nations with which India shares its borders, such as Myanmar and China.
India was declared ‘polio-free’ in March 2014.
“The way polio virus has made a comeback in some Asian countries is not less than a ‘crisis’ situation across the globe. We don’t want to jeopardise the ‘polio-free nation’ tag of India. Hence, we are working on several plans in advance,” a senior officer in the health ministry, who did not want to be named, told ThePrint.
“We are planning to mandatorily vaccinate all Indian travellers who are travelling to polio-infected countries. It will be similar to the advisories given for yellow fever vaccine. However, it needs to be discussed with WHO before the final implementation,” the senior officer said.
ThePrint reached the Press Information Bureau for an official confirmation on this but officers there remained unavailable for comment until the time of publishing this report.
“To prevent any form of poliovirus from entering India, we require very high vaccination coverage, a sensitive surveillance system and a robust routine immunisation programme,” said Dr Naveen Thacker, executive director at the International Pediatrics Association (IPA).
How polio virus is making a comeback
The vaccination for polio — oral polio vaccine (OPV) — contains an attenuated (weakened) vaccine-virus that activates an immune response in the body.
According to the WHO, “When a child is immunised with OPV, the weakened vaccine-virus replicates in the intestine for a limited period, thereby developing immunity by building up antibodies.”
The vaccine-virus is also excreted, it adds. In areas of inadequate sanitation, “this excreted vaccine-virus can spread in the immediate community (and this can offer protection to other children through ‘passive’ immunisation), before eventually dying out”.
If a population is under-immunised, an excreted vaccine-virus can continue to circulate for an extended period of time. The longer it is allowed to survive, the more genetic changes it undergoes.
“In very rare instances, the vaccine-virus can genetically change into a form that can paralyse — this is what is known as a circulating vaccine-derived poliovirus (cVDPV),” the WHO states.
Majority of the nations, especially African nations, are suffering from the outbreak of cVDPV of different types.
“The multiple cVDPV2 outbreaks on the continent of Africa are now at unprecedented levels and need to be treated by countries as a national public health emergency,” WHO had said on 3 October last year.
It also highlighted that the “cVDPV1 outbreaks in Myanmar, PNG and Indonesia and cVDPV3 in Somalia highlight the gaps in population immunity due to pockets of persistently low routine immunisation coverage in many parts of the world”.
Where polio virus still exists
The body had also expressed worry over the widespread transmission of polio in Pakistan where refusal to accept vaccination by individuals and communities has proved to be one of the biggest challenges.
Meanwhile, Nigeria, where not a single case has been reported in the last three years is yet to be considered ‘polio-free’. The country was earlier counted among nations where polio is endemic.