[D9640general] [eFlash_Rotary] Digest Number 711

[Garry & Anne Krischock]

1    1369: Vaccine-derived poliovirus in Nigeria 

Sun Oct 7, 2007 10:52 pm (PST) 
Vaccine-derived poliovirus in Nigeria

As recently reported by various news organizations, 69 cases of polio 
due to a vaccine-derived poliovirus have been confirmed in nine 
northern states of Nigeria. These cases are vaccine-derived, which 
means they came from a changed form of a strain found in the oral 
polio vaccine (OPV).

OPV contains a live but weakened form of poliovirus. On very rare 
occasions, polio strains derived from OPV mutate and regain the 
ability to paralyze and may spread in communities where immunization 
rates are low, especially in densely populated areas where there is 
poor hygiene and poor sanitation.

In the affected areas of Nigeria, polio immunization rates were not 
high enough to protect all children. The vaccine-derived poliovirus 
in Nigeria was first noted in August 2006, and response plans were 
implemented. 

The most effective way to counter such outbreaks is to intensify 
efforts to raise the immunization rates, which means reaching more 
children with the oral polio vaccine. Thus, four mass immunization 
campaigns have been carried out since the outbreak was identified. 

Vaccine-derived polioviruses are extremely rare. Of the more than 10 
billion doses of OPV received by more than two billion children in 
the past 10 years, fewer than 200 vaccine-derived cases have been 
reported, while 6.5 million cases of childhood paralysis were 
prevented. During this same period, the wild poliovirus, our real 
enemy, paralyzed more than 33,000 children.

Tremendous progress has been made toward ending polio worldwide 
through the use of OPV. In the 1980s, 350,000 children were infected 
by this crippling disease each year. In the two decades since, polio 
cases have been slashed by 99 percent. Less than two thousand cases 
were reported in 2006. 

OPV has been the experts' vaccine of choice in over 195 countries 
that have successfully eradicated polio. It remains the Global Polio 
Eradication Initiative's (GPEI) recommended vaccine to finish polio 
eradication.

Source: Rotary International
Courtesy: eFlash_Rotary

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