Wednesday, October 27, 2010

New vaccine has reduced polio worldwide by 90%

From BBC News:

A new vaccine against the polio virus has helped reduce the number of cases by more than 90%.

Research published online in the journal The Lancet, shows that the new vaccine is significantly better at protecting children against polio than the current popular vaccine.

It has already been used in Afghanistan, India and Nigeria.

The scientists behind the work believe this new vaccine could help to finally eradicate the disease.

Mass vaccination campaigns have led to the number of polio endemic countries falling from 125 in 1988 to just four in 2005.

This meant an actual drop in cases from 350,000 to just 1,606 in 2009.

Polio is caused by one of 3 versions of the polivirus: type1, type 2 or type 3.

Until recently, vaccines targetting either all three forms of the virus or just one of them were used to immunisie children.

The last case of type 2 polio was recorded in India in 1999, so it's the other two types that need to be targeted to finally eliminate the disease.

The authors of the study carried out a trial in India comparing the commonly used old vaccines to the new one, which is taken orally.

In total, 830 newborn babies received either the new vaccine or one of the old vaccines in two doses - one at birth and one 30 days later.

Blood samples were taken before vaccination and after the first and second doses to measure seroconversion - the rise in antibodies produced by the immune system against polio.

It appears that the new vaccine is about 30% more effective in protecting against polio than the most commonly used vaccine to date.

The new vaccine has already been used in immunisation campaigns in Afghanistan, India and Nigeria.

In India the number of cases this time last year was 464. Over the same period this year there have only been only 39 cases.

Nigeria has seen an even greater difference, with cases falling by 95%.

The new vaccine and improved immunisation programmes appear to be responsible for this significant decrease, according to the World Health Organization (WHO).

Dr Roland Sutter, from the WHO and the lead author of the study, told BBC News: "This (new) vaccine could get us over the top and get us to the finish line for eradication.

"The dramatic drop in the number of polio cases in India and Nigeria is attributable to the new vaccine and better coverage during immunization campaigns."

The private sector manufacturers played a key role in its development, says Dr Bruce Aylward, the Director of WHO's Global Polio Eradication Initiative.

"They've held the price to the same price of what we are paying for the older polio vaccine," he says.

The new vaccine can be administered in the same way as the previous one. "That's why there is so much promise with this product," says Dr Aylward.

Commenting on the research, Nigel Crawford and Jim Buttery from the Murdoch Children's Research Institute (SAEFVIC) in Melbourne, Australia, said that the new vaccine had shown great promise.

However they cautioned that the global financial crisis had resulted in a massive funding gap for immunisation programmes worldwide, including polio.