The recall is for 1.2 million doses of the vaccine for Hib, which protects against meningitis, pneumonia and other serious infections, and a combination vaccine for Hib and hepatitis B. The vaccine is recommended for all children under 5 and is usually given in a three-shot series, starting at 2 months old.
Drugmaker Merck & Co., which announced the recall Wednesday after this week identifying a sterility problem in a Pennsylvania factory, said concerned parents should contact their child's doctor.
Risk is low
"The potential for contamination of any individual vaccine is low,"
said Merck spokeswoman Kelley Dougherty.
Dr Julie Gerberding, head of the Centres for Disease Control and Prevention, echoed that in a news conference.
"This is not a health threat in the short run, but it is an inconvenience," she said.
Merck produces about half of the nation's annual supply of 14 million doses of Hib vaccine. It said sample vials from the recalled lots, tested before shipment, were not found to be contaminated but the company was unable to assure sterility of the entire lots.
Barbara Kuter, executive director of paediatric medical affairs for Merck, told The Associated Press that because of the contamination, the company will not be able to supply any vaccine for at least nine months.
"Manufacture of vaccines is pretty complicated, and we have to basically make some changes in the process," then get approval from the Food and Drug Administration before resuming production and shipments, Kuter said. Merck hopes to restart production in the fourth quarter of 2008, she said.
Shortage likely
"It's likely that there's going to be a shortage of this product,"
Kuter said, adding that the impact on the public is unclear because the
other company making the vaccine for the US, Sanofi Pasteur, may be
able to produce more.
However, Sanofi Pasteur spokeswoman Donna Cary said Wednesday night that it was too soon to say whether that is possible. The company, a unit of Paris-based drugmaker Sanofi-Aventis SA, makes an Hib vaccine in France that is distributed both to the US and other countries.
"We're looking at what we can add and we're working closely with the CDC on this," to see whether some vaccine could be shifted to the US from other countries, Cary said.
Prioritising shots
Health officials said they already are talking about prioritising
shots for American Indian and Alaska Native children, who are
considered at higher risk for Hib-caused illnesses, said Dr Anne
Schuchat, director of the CDC's National Centre for Immunization and
Respiratory Diseases.
The officials said they did not know how many of the 1.2 million doses were administered to children.
The recalled doses, which were distributed beginning in April, are considered potent, so children who got vaccine from the recalled lots will not have to be revaccinated, Schuchat said.
Parents will probably be concerned, CDC officials acknowledged.
Should the vaccine later prove contaminated, health officials believe most children will experience, at worst, a skin irritation around the vaccination site. Problems could be worse for children with compromised immune systems.
No reports so far
Such problems would have appeared within one week of the
vaccination, Schuchat said, adding that there have been no reports
suggesting vaccine contamination so far.
The contamination involved unspecified equipment used in making the vaccine, which involves taking part of the Hib bacterium, diluting it and combining it with other agents. Kuter said that during a routine evaluation of Merck's West Point, Pennsylvania, vaccine plant, a sterility test determined that the equipment was contaminated with a bacteria called Bacillus cereus, or B. cereus.
It is a spore-making microorganism commonly associated with food poisoning and has caused diarrhoea and vomiting in people who eat contaminated foods.
"It's one of the most common organisms" around, Kuter said.
May ignite debate
The recall is likely to heighten a debate over childhood vaccines
and their safety and whether too many are required. Some parents are
distrustful and suspect some vaccines of being linked to autism,
although scientific studies have not shown such a connection.
Merck, based in Whitehouse Station, New Jersey, is one of the few drugmakers that produces a significant number of vaccines. Its representatives could not immediately say how much revenue the company gets from the Hib vaccine or whether it will have to take an accounting charge due to the production shutdown.
While the company took a black eye with its September 2004 withdrawal of the painkiller Vioxx due to increased risk of heart attacks and strokes, the company has been performing well recently. On Tuesday, it gave an upbeat assessment in its annual briefing for analysts.
Five weeks ago, Merck reached a deal to settle up to 50 000 Vioxx
lawsuits for $4.85 billion (¤3.3 billion), an amount expected to save
the company millions in trial costs. – (Sapa-AP)
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