Smallpox vaccinations seem effective for life

Austin American Statesman ^ | 8/17/03 | Jeff Nesmith

[Oorang]

Smallpox vaccinations seem effective for life

By Jeff Nesmith

WASHINGTON BUREAU

Sunday, August 17, 2003

WASHINGTON — Americans vaccinated for smallpox 50 or more years ago may still be immune to the disease, scientists said Sunday.

Scientists have feared that immunity to the disease has "run out" for people vaccinated prior to the mid-1970s, when vaccinations ended in America.

New research shows that smallpox-specific antibodies remain in the blood of persons who received the vaccine as long as 75 years ago, said Mark Slifka, a viral immunologist at Oregon Health and Science University.

Less plentiful but also present are white blood cells — search-and-destroy T-cells — that are specific to smallpox, he said. Together, the antibodies and the T-cells mean that people who have been vaccinated likely are either immune or resistant enough to have only mild cases, he said.

"That's good news for the people who were vaccinated, and for people who have never been vaccinated also," Slifka said in a telephone interview, "because it means that with from 145 to 150 million Americans walking around with resistance to the smallpox virus, our 'herd immunity' is high."

That means that if the virus were deliberately introduced into the United States, it would spread much more sluggishly than has been feared.

Scientists have assumed that half of the population has never been vaccinated and the other half received its vaccine so long ago that it would not be effective. On this basis, they believed the overall population would be highly vulnerable and the disease would spread rapidly.

Natural smallpox was eliminated in the 1970s by global eradication campaigns organized by the World Health Organization and the Centers for Disease Control and Prevention in Atlanta. Two small samples of the virus were preserved, one at CDC and one in the Soviet Union.

With the end of the Cold War, U.S. intelligence and public health officials have concluded that the Soviets violated agreements and experimented with the smallpox sample, possibly developing large reserves of the virus for use as biological weapons.

Since the whereabouts of this virus is now unknown, the U.S. Departments of Health and Human Services and Defense have contracted for development of new vaccines.

Smallpox immunity results from having a related disease, vaccinia.

Since Slifka and his associates do not have access to smallpox virus, they exposed serum samples of hundreds of persons who have been vaccinated to new vaccinia virus, using the vaccinia as a stand-in for smallpox. The tests revealed vigorous antibody action and smaller quantities of T-cells.

Since the antibodies and T-cells that react against vaccinia are the same ones that protect against smallpox, the scientists concluded that smallpox immunity also remains high.

Slifka and other scientists at the Oregon university published their conclusions Sunday in the journal Nature Medicine.

[Oorang]

Well, I wish they would make up their mind as to the life expectancy of these vaccines.

[Dog Gone]

I want my scar to still mean something, dang it.

[Lucy Lake]

Ping...

[Sabertooth]

FYI

[Stefan Stackhouse]

When I was a kid and received my smallpox vaccination, I distinctly remember being told that it would protect me for life. I do not have any memories of any adults back then talking about getting re-immunized.

[EggsAckley]

Not too long ago they were positive that the older shots had NOT retained the immunity. I wonder which prescription drug mogul is not happy tonight.

[John Beresford Tipton]

fyi

[John Beresford Tipton]

I think you needed a shot within five years for readmittance to the US. I must have had 5 smallpox shots prior to their stopping them.

[LadyDoc]

based on population studies, they knew that after 7 years people started coming down with the disease even if they were vaccinated.

You retain partial immunity, however, and probably won't die, but you might be sick.

The bad news is that if smallpox is used as a bioweapon, few people under age 35 have ever had a vaccination. And, of course, the Russians had tons of biologically changed smallpox that over came this immunity...

[Atchafalaya]

Can I sell my stock now?

[blam]

Thanks for the ping. I thought we had decided a few months ago that there is benefit from a real old shot.

[John Beresford Tipton]

Yes, this article just confirms what the prior article said.

[Bella]

I seem to remember this also.

[bonesmccoy]

Have you seen any references to the actual scientific study?

I'd like to reserve judgement.

We need to review the basis for this substantial rewrite of the current understanding of immunologic response to live virus vaccines.

If this is the case, why are we doing booster doses of MMR?

MMR should be dosed later and then not boosted.

Varicella is not boosted because it is thought to have life long immunity.

How is it that MMR does not confer this lifelong immunity (is it due to the age we dose the vaccine?) but smallpox and varicella vaccines do?

[King Prout]

well, that's nice, but I'm still getting my booster next month.

[Sabertooth]

How is it that MMR does not confer this lifelong immunity (is it due to the age we dose the vaccine?) but smallpox and varicella vaccines do?

I'm a cat, Bones, not a doctor.

[boris]

I told a retired doc (I work out with him) that I wanted a booster.

"Nope."

"Why?"

"You're 52, have diabetes and cardiac conditions. The danger to you of the shot would be higher than the risk of getting smallpox."

Or so he claimed. The problem is, you cannot even get a booster if you are not a "health care" provider or law enforcement.

Would be nice to have the choice, no?

--Boris

[bonesmccoy]

well I AM a doctor and if I can't answer that damn question, the bureaucrats at the Federation sure as hell can't either.

The question was rhetorical!

(now, where is that green blooded S.O.B. that keeps attacking me with his katra?)

LOL/just kiddin!