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Immune Memory From Smallpox Vaccination Last More 50 Years, According To Emory Research
Science Daily ^ | 11-12-2003 | Emory University

Posted on 11/12/2003 10:00:42 AM PST by blam

Source: Emory University Health Sciences Center
Date: 2003-11-12

Immune Memory From Smallpox Vaccination Lasts More 50 Years, According To Emory Research

ATLANTA -- Immune memory after smallpox vaccination persists for at least 50 years in immunized individuals, according to research conducted by scientists at the Emory Vaccine Center and Emory University School of Medicine. This is good news, since the findings, published in the Nov. 15 issue of the Journal of Immunology, suggest that individuals vaccinated against smallpox prior to the end of the smallpox vaccination program in 1972 may still retain at least some protection against smallpox.

Rafi Ahmed, PhD, Georgia Research Alliance Eminent Scholar and director of the Emory Vaccine Center, was principal investigator of the research study, and Shane Crotty, PhD, formerly at Emory University School of Medicine and currently a faculty member at The La Jolla Institute for Allergy and Immunology, was first author. Other members of the research team included Emory microbiologist John Glidewell, Phil Felgner, and Luis Villarreal of the University of California, Irvine, and Huw Davies of King's College London.

Although scientists have known that acute viral infections and vaccines produce two types of long-term immune memory that provide protection against disease, they are still learning the details of these immune mechanisms.

Using a new blood test they developed to assess human antigen-specific immunity, the Emory scientists measured memory B cell responses in individuals recently vaccinated with smallpox vaccine (DryVax), in unvaccinated individuals, and in individuals vaccinated between three months and 60 years earlier. The recently vaccinated group showed a significant virus-specific memory B cell response to vaccinia, while the unvaccinated individuals were negative for vaccinia virus-specific memory B cells. Vaccinia virus-specific B cells were detected in most of the previously vaccinated individuals in the study, including those vaccinated up to 60 years after vaccination.

The scientists found that virus-specific memory B cells initially declined after smallpox immunization, but then reached a plateau approximately ten times lower than their peak, where they remained stable for more than 50 years. Although there were significantly fewer memory B cells in the most recently vaccinated group compared to those vaccinated decades earlier, there was no significant change in B cell memory between 20 and 60 years after vaccination. In addition, individuals vaccinated against smallpox maintained anti-smallpox antibodies in their blood for at least 60 years after vaccination, with no indication of decline between 1 and 60 years.

In humoral immunity, the body's first line of defense against infection is antibodies produced by B cells, which are the primary measure of immunity for most vaccines. Memory B cells are responsible for stimulating a rapid antibody response after re-exposure to infection. In cellular immunity, activated T cells kill specific virus-infected cells and also produce cytokines –– proteins that prevent the growth of viruses and make cells resistant to viral infection. Previous studies in mice by Dr. Ahmed have shown that B cell memory can persist even without re-exposure to viral antigens, but this had not yet been demonstrated in humans.

In order to test the functionality of the memory B cells, the scientists revaccinated a group of test subjects who had been vaccinated between 22 and 48 years earlier, and detected 20-fold increases in vaccinia-virus antibodies after the second vaccination. They also tested antibody response to a specific viral protein. In previously immunized individuals they detected an antibody response prior to booster immunization as well as a strong response four weeks after booster immunization. In newly vaccinated individuals, however, the antibody response to the specific viral protein was virtually undetectable.

"The fact that there was an antibody response to this viral protein in individuals vaccinated years earlier, but no response in recently vaccinated individuals, demonstrates the potency and value of maintaining a pool of memory B cells for decades after vaccination," notes Dr. Crotty. The researchers also measured vaccinia-virus-specific T cells, and found that although the level of T cells declined gradually over time, the cells still were present even decades after immunization in most study subjects.

"Immune memory to smallpox vaccination is an excellent benchmark to help us understand the mechanisms of good vaccines and also to understand the longevity and stability of immune memory in the absence of revaccination or disease," said Dr. Ahmed. "Our findings may be useful as decisions are made about re-instituting a smallpox vaccination program. And because smallpox has an incubation period of from 12 to 14 days, this provides a window of opportunity for memory B and T cells to expand and attack the infection before the onset of clinical disease."

Dr. Crotty said, "Our findings may help assist health authorities in their decision-making process about updates or changes to the smallpox vaccination program. Our work has not shown that these people would be protected, because that cannot be directly tested, and this is an important point. But, our study does show that people maintain immune memory against smallpox for many decades, and hopefully those levels of immune memory would provide at least some amount of protection against smallpox."

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This story has been adapted from a news release issued by Emory University Health Sciences Center.


TOPICS: Culture/Society; News/Current Events; War on Terror
KEYWORDS: 50; immune; memory; smallpox; vaccination; years
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The question of long term immunity to smallpox from vaccinations decades ago has been asked many times here on FR.
1 posted on 11/12/2003 10:00:42 AM PST by blam
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To: aristeides
Ping.
2 posted on 11/12/2003 10:01:13 AM PST by blam
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To: blam
Thanks. Good read!
3 posted on 11/12/2003 10:02:44 AM PST by Van Jenerette (Our Republic...if we can keep it!)
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To: blam
Thanks for the post. I know many of us older Freepers had been wondering if the vaccinations we had as kids would still be effective in the event of a Religion of Peace® smallpox attack.
4 posted on 11/12/2003 10:05:46 AM PST by spodefly (This is my tagline. There are many like it, but this one is mine.)
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To: blam; bonesmccoy; David Hunter; Jim Noble
Rafi Ahmed, PhD, Georgia Research Alliance Eminent Scholar and director of the Emory Vaccine Center,

I just hope he's really on our side and not the terrorists.

5 posted on 11/12/2003 10:09:33 AM PST by Paleo Conservative (Do not remove this tag under penalty of law.)
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To: blam
And this opens up a different question. Scientists and doctors tell us that virus and bacteria evolve fairly rapidly. Then why hasn't the smallpox virus evolved to simply avoid the vaccine antibodies?
6 posted on 11/12/2003 10:15:29 AM PST by Blood of Tyrants (Even if the government took all your earnings, you wouldn’t be, in its eyes, a slave.)
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To: blam
P.S. Is the military still vaccinating personnel agains smallpox? They were in the early 80's.
7 posted on 11/12/2003 10:16:34 AM PST by Blood of Tyrants (Even if the government took all your earnings, you wouldn’t be, in its eyes, a slave.)
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To: Blood of Tyrants
Because the disease was eradicated from the population, and the only strains of smallpox that exist all come from from just a couple of laboratories.

8 posted on 11/12/2003 10:19:17 AM PST by wimpycat ("I'm mean, but I make up for it by bein' real healthy.")
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To: Blood of Tyrants
yes, the started vaccinating again before going into Iraq
9 posted on 11/12/2003 10:24:12 AM PST by iceskater
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To: Blood of Tyrants
No, not for the longest time, but I believe they are starting up again. I retired in 1998, but had my last smallpox vaccine in 1979.
10 posted on 11/12/2003 10:24:30 AM PST by Alas Babylon!
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To: genefromjersey
ping
11 posted on 11/12/2003 10:24:36 AM PST by Calpernia (Innocence seldom utters outraged shrieks. Guilt does.)
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To: blam
Well....looks like I'm safe for about 2-3 more years.....
12 posted on 11/12/2003 10:33:19 AM PST by goodnesswins (We are living in fantastic times....the breakup of the US DEM-Commie Party is in progress)
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To: wimpycat
Not acceptable. Smallpox vaccinations have been available since the early 19th century.
13 posted on 11/12/2003 10:37:22 AM PST by Blood of Tyrants (Even if the government took all your earnings, you wouldn’t be, in its eyes, a slave.)
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To: Blood of Tyrants
Scientists and doctors tell us that virus and bacteria evolve fairly rapidly. Then why hasn't the smallpox virus evolved to simply avoid the vaccine antibodies?

Because antibodies recognize and directly attack the physical structure of the organism.

Antibiotics are like dumb bombs. They rely on the physiology of the bug to do their work, and the bugs are pretty good at altering their physiology to compensate.

Antibodies are billions of years old-they have been evolving for all that time. They attack physical properties of the organism that are much harder (or impossible) to change.

14 posted on 11/12/2003 10:44:46 AM PST by Jim Noble
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To: Jim Noble
Anyone know how similar chicken pox is to small pox? Children are being vaccinated against chicken pox now. What is the opinion for this building immunities against small pox?
15 posted on 11/12/2003 10:49:05 AM PST by Calpernia (Innocence seldom utters outraged shrieks. Guilt does.)
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To: blam
The human immune system seems to have a capacity issue when it comes to immunity which is not referenced in this article. The system seems to handle thirty responses at a time. It will discard least used immunity responses in favor of newly introduced or most heavily needed exposures. This is one of the reasons that individuals can suddenly find themselves sickened by something which never before bothered them. It is also the purpose of boosters. The booster just tells your system that this nasty virus is still on the thirty most needed list and prevents it from being dropped in favor of that flu shot from three years back.

I'm not a details guy. I remembered it here on FR about two years ago as a sourced story and since then, it's been mentioned at my livestock seminars as it highlights the need for boosters.

16 posted on 11/12/2003 10:49:11 AM PST by blackdog (Five clicks gets you 2600' of bright soft grass in the murkiness of night.)
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To: Blood of Tyrants
What do you mean "not acceptable"? My answer may be incorrect, but "unacceptable"? I know smallpox vaccinations have been available for a long time. They used to use cowpox virus. That's how inoculation was discovered. They figured out that people who got cowpox never got smallpox.

The disease has been eradicated from the populace, though. The last known case was somewhere in the 3rd world, in the early 1970's. So that much is fact. Smallpox vaccinations are derived from the smallpox virus. The only live smallpox virus in existence today is that grown and kept alive in only a few laboratories. The U.S. had some, the Brits had some, and the Soviets had some. Maybe a couple other labs have it, too. If any smallpox fell into the wrong hands, chances are it came from the Russian labs.

Unlike influenza and the common cold, which have many different strains and seem to be constantly mutating, I don't believe the smallpox virus changes all that much, anyway.
17 posted on 11/12/2003 10:51:02 AM PST by wimpycat ("I'm mean, but I make up for it by bein' real healthy.")
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To: Jim Noble
See my post on the list of thirty. That is also how your system adapts to mutations in a virus for which you had been immunized. It does have it's own way of rotating the older versions out and adapting to the newer ones.

Our creator was a brilliant designer(except for abuse and intentionally inflicted damages)

18 posted on 11/12/2003 10:52:39 AM PST by blackdog (Five clicks gets you 2600' of bright soft grass in the murkiness of night.)
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To: blam
Thanks.
19 posted on 11/12/2003 10:53:09 AM PST by DoctorMichael (Thats my story, and I'm sticking to it.)
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To: Calpernia
Small pox is related to cowpox. As far as I know, it's not similar enough to chicken pox for someone to have immunity to smallpox after catching chicken pox.
20 posted on 11/12/2003 10:53:13 AM PST by wimpycat ("I'm mean, but I make up for it by bein' real healthy.")
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