A new vaccine used in US children since 2000 has slashed deadly pneumococcal bacteria infections in older adults, experts said on Sunday.
It may help reduce deaths from influenza, too, the experts told a conference. The vaccine, Prevnar, is made by Wyeth Inc. and protects children against seven strains of Streptococcus pneumonia bacteria.
These pneumococcal bacteria are believed to be the most common causes of pneumonia and also cause ear infections, meningitis and deadly blood infections.
It is recommended that the vaccine be given to children in four doses, at two months, four months, six months and 12 to 15 months of age.
"This vaccine is interrupting transmission between adults and children," Dr Keith Klugman of Emory University in Atlanta told a news conference.
"This in fact reducing the burden of disease in adults." Dr Klugman reviewed several US studies that have found that since Prevnar was introduced in 2000, fewer adults have become infected with deadly strains of pneumococcus - especially those that had begun to resist antibiotics.
"In children the vaccine is reducing invasive disease... by... 85 to 90 per cent. It is a dramatic reduction," Dr Klugman told the meeting of infectious disease experts sponsored by the American Society for Microbiology.
"In adults the effect is about a 35 per cent reduction." There is an adult vaccine that protects against 23 strains of bacteria - but the reduction in infections has only been seen in the seven strains covered by Prevnar, Dr Klugman said.
Dr Klugman also believes the vaccine may help reduce deaths and complication from influenza.
Influenza is caused by a virus, but many of its deadliest and most health-threatening complications can be caused by bacteria causing pneumonia and blood infections.
In August, his group reported in the journal Nature Medicine that 45 per cent of pneumonias associated with influenza could be prevented by use of a different pneumococcal vaccine, also made by Wyeth.
The vaccine prevented 31 per cent of any types of pneumonia associated with seven different respiratory viruses, they found in the study of 37,000 South African infants.
Before a vaccine was available, pneumococcal infections caused more than 700 cases of meningitis, 13,000 blood infections and about five million ear infections every year in the United States alone, according to the US Centres for Disease Control and Prevention.
Despite shortages that caused slight rationing of the vaccine for two years, Prevnar has been wildly successful. Wyeth has said Prevnar is on target for sales of $1 billion this year - more money than any vaccine has ever made.
"To date, it's just the United States that has any history with this vaccine," Dr Klugman said.
More children die of pneumococcal disease in the developing world, but Dr Klugman said companies do not see that market as profitable.