CDC to Destroy Oldest Smallpox Vaccine

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CDC to Destroy Oldest Smallpox Vaccine

By MIKE STOBBE – 19 hours ago

ATLANTA (AP) — The government announced Friday that it has said

goodbye to one of the world's greatest lifesavers — the oldest

smallpox vaccine. The U.S. Centers for Disease Control and Prevention

this month made arrangements to dispose of the last of its 12 million

doses of Dryvax, and notified other health departments and the

military to do the same by Feb. 29.

Dryvax — produced by scraping virus off the skin of infected calves —

is being replaced in federal vaccine stockpiles by a more modern

product manufactured in laboratories.

Dryvax was unusually dangerous for a vaccine, blamed in recent years

for triggering heart attacks and a painful heart inflammation in some

patients.

Still, attention should be paid on the occasion of its demise, said

Dr. Schaffner, chairman of Vanderbilt University's department

of preventive medicine.

It is a " historical moment, because it's our oldest vaccine, "

Schaffner said. " It was a vaccine that eliminated smallpox from the

United States. "

Smallpox is a deadly, infectious disease that plagued the world for

centuries and killed nearly a third of the people it infected. Victims

suffered scorching fever and body aches, then spots and blisters that

would leave survivors with pitted scars.

Dryvax was created in the late 1800s, by the company that became Wyeth

Laboratories. Wyeth was a primary U.S. manufacturer of smallpox

vaccine by the mid-1940s, and was the only company left making it by

the early 1960s, said Dr. D.A. , a University of Pittsburgh

vaccine expert who played a key role in international smallpox

eradication efforts.

The United States was able to end routine childhood vaccination

against the disease by the early 1970s. World health authorities

declared the disease was eradicated from nature in 1980.

Wyeth stopped making the vaccine in the 1980s. But government

officials kept a stockpile of about 15 million doses. The Dryvax came

in handy in 2003, when it was used to help contain an outbreak of

monkeypox in the United States.

" There are situations where one does have to have a smallpox vaccine, "

said Dr. Neal Halsey, director of Hopkins University's Institute

for Vaccine Safety.

U.S. officials had also been worried that smallpox might resurface as

a result of bioterrorism. Following the 9/11 attacks and the

anthrax-containing letters that surfaced a month later, the government

in 2002 ordered certain military personnel vaccinated and recommended

shots for front-line health care workers.

The government also pushed for manufacture of a new vaccine. It hired

a company named Acambis Inc., which had produced nearly 200 million

doses by the end of 2003, said.

Last September, the U.S. Food and Drug Administration approved

licensure of the company's ACAM2000 vaccine. That product is now the

mainstay of the CDC stockpile, said.

Dryvax had problems. It was long suspected of triggering neurological

complications, including encephalitis, in rare cases. Then, in 2003,

three adults who received the vaccine died suddenly of heart attacks.

As a precaution, health officials advised people with heart disease to

skip the vaccination.

A study published in 2005 suggested that Dryvax triggered a painful

heart inflammation in a small number of emergency workers vaccinated

after Sept. 11.

" Times had changed, and our awareness, sensitivity and tolerance for

adverse events associated with vaccines was much greater " than during

the smallpox vaccination campaigns of the 20th century, Schaffner said.

ACAM2000 is created in laboratories, not on a farm, so there's much

less possibility of bacterial contamination in the production process.

However, it's derived from Dryvax, and it's not clear it will have

fewer side effects than the old vaccine, some vaccine experts said.

On the Net:

* CDC: http://emergency.cdc.gov/agent/smallpox/vaccination/index.asp