Makers of Flu Vaccine Are Behind Schedule
If you’re the type who likes to get a flu shot early in the fall, take note. Most people are going to have to wait until November to get the vaccine.
Vaccination campaigns that normally begin in October have been pushed back a month because of difficulties producing vaccines against new flu strains. Health officials, meanwhile, are hoping a shortage doesn’t develop.
With the four manufacturers of U.S. flu vaccines about a month behind their typical delivery schedule, doctors have been advised to first vaccinate the highest-risk patients--the elderly, those 50 to 64 with chronic diseases and pregnant women--and health care workers. These groups will be vaccinated as soon as supplies become available; mass vaccination of healthier Americans should follow.
Each year, scientists at the World Health Organization and federal Centers for Disease Control and Prevention in Atlanta predict which strains are the likeliest to create a problem in the coming year. In the last two years, they targeted A/Sydney and A/Beijing strains as well as a B strain. But for the 2000-2001 season, infectious disease experts determined that two new A strains were likely to be troublesome: Type A/Panama and A/New Caledonia, along with B/Yamanashi, a carry-over from last year.
This year’s production delays stem from problems encountered by the four companies that supply the U.S. with vaccines, which are made from inactivated flu viruses.
Although they use slightly different technology, all had trouble generating enough of the A/Panama component of the vaccine, which was only identified in late April as a new target.
Aventis Pasteur, which supplies more than half the U.S. flu vaccine supply, normally begins shipping its vaccine in late July or early August. It has been in round-the-clock production “putting the pedal to the medal” and sent out its first shipments the first week of September, said spokesman Len Lavenda.
Further stalling this year’s production were quality control violations and other manufacturing issues that Parkedale Pharmaceuticals Inc. and Wyeth-Ayerst Laboratories Inc. have been working with the FDA to clear up. Medeva Pharma Ltd., a British company, is the fourth U.S. supplier.
Beyond the delays, “we don’t know how much vaccine will get to the marketplace,” Lavenda said. Charlis Thompson, a CDC spokeswoman, predicted that there should be some indication about the supply by the end of September.
Typically, public health officials conduct immunization campaigns in October and early November. That gives them time before the arrival of the winter flu season, which usually begins in December and continues through March.
To avoid having patients show up at clinics and offices only to find out vaccine supplies have dried up, the CDC advised that health-care providers, health organizations and other groups planning mass vaccination campaigns for the 2000-2001 season postpone those programs until November.
“We feel confident that even receiving the vaccine in November or getting the vaccine throughout the season while the virus is circulating is going to be of tremendous public benefit,” Thompson said.
No one knows how closely this year’s delayed vaccination campaigns will bump up against outbreaks of the illness, but last year, flu activity began to increase in mid-December and peaked during the weeks ending Dec. 25 and Jan. 15, 2000, CDC surveillance data show. Widespread flu was first reported the week of Dec. 18.
It typically takes about two weeks after vaccination for a person’s body to develop enough antibodies to protect against an assault by the virus, but maximum immunity is reached at about four weeks, said Dr. Robert Fick, a pulmonary specialist who teaches at Stanford University. Because flu cases often peak in February, vaccination in November or later still can be valuable.
The CDC earlier this year recommended that people 50 to 64, not just those 65 and over, be vaccinated. In light of the production logjam, it has advised doctors to make contingency plans in case of shortfalls by first vaccinating the elderly, those who live in nursing homes and those 50 to 64 who suffer from heart, lung or kidney problems, diabetes or severe anemia, because they’re particularly vulnerable to potentially life-threatening flu complications. Anyone with an immune disorder or any woman in the second or third trimester of pregnancy also should be a priority, CDC said.
Natalie Smith, the immunization branch chief for the state health department, also said that the strategy of vaccinating those at high risk first should work. “Maybe the healthy younger folks can wait a little bit,” she said.
In all, as many as 76 million people are at high risk for serious complications from the flu, which commonly leads to 20,000 deaths and more than 110,000 hospitalizations each year.
The flu infects the respiratory tract and can cause high fever and major complications including pneumonia, which can be deadly.
Flu spreads through the air from sneezing and coughing or through close physical contact.
“Vaccination against the flu is the best defense against complications of the flu, which are quite substantial,” said Dr. Norman H. Edelman, a scientific affairs consultant to the American Lung Assn., and medical school dean at the State University of New York at Stony Brook.
However, he said, physicians will have to decide whether or not to use any of the four prescription drugs that may ease the illness.
Two of the drugs, zanamivir and oseltamivir, marketed as Relenza and Tamiflu, respectively, were rolled out last year. They belong to a class of drugs called neuraminidase inhibitors and can reduce the severity and duration of flu infections with A and B strains.
There are two antiviral medications effective against Type A flu strains, amandatine and rimandatine, which are FDA-approved for treating and preventing influenza A. However, because both drugs can produce neurological and other side effects, they’re not recommended for widespread use except in the case of potentially devastating outbreaks.
