By David
Brown
Shots designed to protect children
against eight of 11 vaccine-preventable infections have been intermittently
in short supply everywhere in the United States since last summer.
Some will remain hard to get
for at least another six months.
"This is unprecedented,"
said Walter A. Orenstein, a physician who directs the National Immunization
Program for the federal Centers for Disease Control and Prevention (CDC)
in Atlanta. "I have never seen anything like the supply problems
with this many vaccines in the 24 years I've worked in immunization."
There's no single cause behind
the shortages. Instead, they've arisen from a combination of business
decisions, bad luck and greater than expected demand for the vaccines.
The vaccines in short supply
are the:
- DTaP triple-combination
that protects against diphtheria, tetanus and pertussis (also known
as "whooping cough");
- MMR, another triple combination
that protects against measles, mumps and rubella;
- Pneumococcal conjugate,
which protects against seven strains of the bacterium Streptococcus
pneumoniae; and
- Varicella vaccine, which
protects against chickenpox.
The current troubles began
with the announcement by the pharmaceutical company Wyeth Lederle in January
2001 that it would stop making vaccines containing tetanus and diphtheria
components.
This immediately cut the supply
of DTaP, a mainstay of childhood vaccination that every American is supposed
to get five times by age 6. It also reduced the amount of Td vaccine,
the classic "tetanus shot" people get when they have dirty wounds.
With few exceptions, that one is now available only in emergency rooms.
Only one company, Aventis Pasteur,
makes Td, and only two, Aventis and Glaxo SmithKline, make DTaP. Although
each is boosting production, they've been unable to meet demand.
This precipitous drop in supply
was worsened by the fact that Aventis
Pasteur's DTaP contained thimerosal, a mercury-based antibacterial compound
put in vials holding multiple doses.
In
1999, the CDC asked manufacturers to take thimerosal out of childhood
vaccines.
The company now makes only
single-dose vials, each of which must be slightly overfilled because the
entire volume can never be pulled out by the syringe. This unavoidable
waste effectively reduces the vaccine yield by about 25 percent.
At the same time the DTaP shortage
emerged, Wyeth Lederle experienced a run on Prevnar, the S. pneumoniae,
or "pneumococcal," vaccine it launched in February 2000. By
last September, the company had distributed what it expected to sell for
all of 2001. The CDC stepped in and recommended that doctors defer the
last of the four recommended doses until production caught up.
Merck & Co., the other
major U.S. vaccine maker, has also had production problems. It shut down
its sole vaccine plant for repairs for a week in August and for nearly
all of October. This interrupted the supply of MMR vaccine and chickenpox
vaccine, both made only by Merck. Full production didn't resume until
February, and there has been spot shortages of both vaccines for months.
The shortages stem, in part,
from the fact that only a handful of U.S. companies still make vaccines.
A generation ago, there were about 20 producers -- a number that included
some state health departments. There's been nothing short of a stampede
away from the business.
There are many reasons for
this, starting with the fact that vaccines historically have been high-volume,
low-profit items in drug companies' catalogues. This is still true of
older vaccines.
The CDC paid about $11 for
a dose of MMR in 1987; the price is only $15.50 today. Only the newer,
still-under-patent products such as the chickenpox vaccine ($39 a dose,
at the government discounted price) and the pneumococcal vaccine ($46)
offer the kind of profit margins pharmaceutical companies are accustomed
to. Furthermore, because the federal government buys so much, discount
pricing is the rule, not the exception, in the vaccine market.
Vaccines are also hard to make.
They're derived from bacteria and viruses, which are trickier to handle
than inert chemicals. Many require elaborate processing to keep them safe,
uncontaminated but still active. It takes Aventis Pasteur almost a year
to make a batch of Td. Wyeth Lederle's Prevnar takes six months, with
each batch spending time at a plant in New York and at another in North
Carolina.
As with the making of drugs,
vaccine production is heavily regulated by the Food and Drug Administration,
and companies must periodically spend large amounts of money on plant
improvements to meet the FDA's requirements. Many complain that they can't
recoup their investment through sales.
In fact, that's part of the
reason Wyeth Lederle bailed out of DTaP production. A competitor is working
on a vaccine that would combine DTaP with polio and hepatitis B vaccines,
potentially making Wyeth's product obsolete. Spending money on a plant
to keep making the old vaccine was simply viewed as not worth it.
Vaccines
account for only 1.5 percent of the global pharmaceutical market.
Among the economic disincentives
is the fact that vaccines are given on a rigid schedule and only occasionally
-- far different from products such as antidepressants and cholesterol-lowering
drugs, which are taken for years and whose "target" populations
are constantly expanding.
Moreover, vaccine hazards stand
out starkly in populations in which the diseases the vaccines prevent
are no longer visible.
"When you are dealing
with a healthy child, any side effect is viewed as unacceptable,"
said Wayne Pisano, executive vice president of Aventis Pasteur in North
America.
In the 1980s, when publicity
about a rare, sometimes disabling complication from the old form of the
pertussis vaccine caused a rise in lawsuits and a drop in immunization,
Congress enacted the no-fault Vaccine Injury Compensation Program, which
handles such claims. Nevertheless, many drug companies now fear that the
program won't shield them from a new wave of lawsuits arising from the
rumors of new, unproved, vaccine complications.
Edited
from Washington Post April 20, 2002; Page A01
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