Climate Change Migration Could Complicate Polio Eradication Efforts

This news article from Reuters AlertNet examines on how climate-change-induced migration may complicate polio eradication in India, one of the 4 endemic countries globally still grappling with complete eradication of the infection.

India has a long history of worker migration, and growing climate-related movement necessitated by unpredictable rains and fluctuating farm income threatens to undo some of the gains in eradicating polio, particularly since migrants often end up in slums with poor sanitation, where chances for transmission of the virus are high. (The polio virus lives in the throat and intestines of affected children, and passes to others through contact with the faeces of the infected child. Open defaecation can suspend the virus in the air, allowing it to enter the body through nose or mouth, health officials said.)

As detailed here, whereas in their home villages parents are often aware of how to ensure that their children receive the several rounds of oral polio vaccine (OPV) needed to achieve effective production, they may be lacking information in the large city to which they have migrated (e.g., Delhi). One migrant mother quoted here explains, "We have heard the radio announcing polio day. But unless they come here, how can we give the drops?" As noted here, Delhi slum dwellers may feel little sense of urgency that their children should be vaccinated, in part because they face so many other pressing health and economic problems. In recent years, all polio cases in Delhi have been among children living in slums, mostly migrants or those living in close proximity to migrants from the endemic states, health officials said.

Other information needs, even in smaller villages where it is easier to access OPV (e.g., through door-to-door rounds), are related to combating rumours. As reported here, the government's keenness to vaccinate repeatedly and the huge amount of resources committed to the programme has led to unfounded suspicions that the programme has some other hidden agenda - e.g., rumours have spread that the polio drops cause sterility.

In response, India's government has set up a tracking system for pregnant women and newborns, designed to ensure that the children of migrants get needed polio vaccinations regardless of where they are living at the moment. Individuals, known as "informers", are chosen by district governments to alert field staff when families migrate away from or return to villages. The informers generally are people with strong local knowledge or influence, including village health workers, large landowners (whose farmhands may move), shopkeepers, and close relatives who can provide exact information about new settlement locations.

In addition to tracking down migrants in their new locations, vaccinators station themselves at transit points like bus and railway stations, police checkpoints, toll stations, and temporary shanties at migrant-rich places like isolated brick kilns and construction sites.