Fewer Prevnar doses just as effective

LONDON (Reuters) - Two or three doses of Prevnar, the childhood vaccine against pneumonia, meningitis and blood infections, are as effective as the standard four doses -- and less expensive, researchers said on Friday.

Made by the drug company Wyeth, Prevnar has been used in the United States since 2000. It is usually given four different times to babies during the first 12-15 months of life.

But new research published in The Lancet medical journal showed it prevented infections in children who received fewer than the recommended number of doses.

"The vaccine is effective when used in various non-standard schedules," said Dr. Cynthia Whitney of the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta.

She noted that in addition to being cheaper, babies do not enjoy being vaccinated and that parents and doctors would prefer to give children as few injections as possible.

The vaccine protects children against seven strains of Streptococcus pneumonia bacteria that cause serious childhood illnesses and ear and sinus infections.

Its popularity led to shortages between 2001 and 2004 and doctors could not always give children the recommended number of doses.

Whitney and her colleagues compared the effectiveness of different doses in 782 children who were at risk of pneumococcal disease because of conditions, such as chronic illnesses, and 2,512 other children.

They found the effectiveness of two, three or four doses in preventing infection was very similar up to six months after vaccination. Even after more than six months, there was no significant difference in the impact of the doses.

"Our data suggest that several schedules afford good individual protection, although we could not show protection for one dose given before six months of age," Whitney added.

The researchers said their findings indicate that vaccines have the potential to greatly reduce the 800,000 to 1 million deaths that occur from pneumococcal disease every year.

"The next challenge is to ensure that conjugate vaccines become part of routine immunization in more places, especially in developing countries where most pneumococcal deaths in young children occur," Whitney added.