Featured Research

from universities, journals, and other organizations

Smallpox Vaccine Provides More Protection Than Previously Thought

Date:
May 26, 2003
Source:
Oregon Health & Science University
Summary:
Researchers at Oregon Health & Science University this week announced preliminary study results showing smallpox vaccine protection lasts longer than previously thought. Until now, it was widely accepted that smallpox vaccine protection lasted approximately three to five years. However, early study data shows that significant, partial protection may last many decades after inoculation.

PORTLAND, Ore. – Researchers at Oregon Health & Science University this week announced preliminary study results showing smallpox vaccine protection lasts longer than previously thought. Until now, it was widely accepted that smallpox vaccine protection lasted approximately three to five years. However, early study data shows that significant, partial protection may last many decades after inoculation. “More than 90 percent of Americans older than 35 have already been vaccinated against smallpox. This translates into about 150 million people who are likely to have at least some level of detectable immunity against this disease,” said Mark Slifka, Ph.D., a researcher at the OHSU Vaccine and Gene Therapy Institute. Slifka and his colleague Erika Hammarlund presented the initial findings at this week’s meeting of the American Society for Microbiology in Washington, D.C.

Related Articles


To conduct their research, Slifka and his colleagues studied blood samples taken from 306 people who had received smallpox vaccinations. These immunizations occurred as recently as one month prior to testing and as long ago as 75 years. Scientists concentrated on two types of immunity in these patients. The first form of immunity is linked to levels of antibody produced in the body in response to the vaccine. These antibodies protect patients by forming the first line of defense against smallpox if an exposure occurs. The second form of immunity is T-cells programmed by the vaccine to attack the smallpox virus.

“What we found was that while T-cell immunity declines slowly over time, antibody immunity can last throughout a person’s life,” said Slifka. “Remarkably, we were able to identify some types of virus-specific immunity in volunteers who were vaccinated up to 75 years ago, indicating that their immune systems remembered the virus for three-fourths of a century after smallpox vaccination. These results are likely to have a profound impact on current models and theories on how rapidly smallpox would spread in contemporary populations because immunity following smallpox vaccination is lasting much longer than people expected.”

However, Slifka believes the pre-event vaccination of first-responders, the military, or members of smallpox task force teams remains necessary. “People with a potential occupational risk for exposure to smallpox should still be vaccinated as a safety precaution” he said. “Likewise, in the event of a smallpox outbreak, those who have come into contact with smallpox victims should be vaccinated or revaccinated as a fundamental safeguard against contracting the disease, and this serves as an important measure against spreading smallpox to others.”

Another important finding of the study was that people who had received vaccinations several times in the past had essentially the same immunity level as those vaccinated once or twice. Researchers believe immunizations create a short-term burst of higher immunity that, over time, appears to return to a set point no matter how many times a person has been vaccinated.

The smallpox vaccine’s active ingredient is a virus called vaccinia, that is closely related to smallpox. However, unlike smallpox, vaccinia does not cause serious health problems in most patients. The virus promotes smallpox protection by causing the body to produce protective antibodies and white blood cells that can search for and destroy smallpox-infected cells.

Future studies in the Slifka lab will focus on determining the level of immunity that could be considered protective in the case of an outbreak. This information would help health officials determine which members of the previously vaccinated population are at highest risk. It would also guide emergency health providers in making decisions about vaccination priorities.

“This research helps illustrate how world events have refocused scientific research and resources to better respond to major health threats that could have devastating effects,” added Jay Nelson, Ph.D., director of the Vaccine and Gene Therapy Institute. “OHSU has proposed a number of initiatives to aid in this national effort.”

Slifka and many of his colleagues are part of the newly formed Pacific Rim Biodefense Center (PRBC). The PRBC is a collaborative effort headed by OHSU. Member institutions will investigate new ways to fight infectious diseases – spread through natural causes or bioterrorism – that threaten human health. The PRBC includes the University of Hawaii at Manoa; the University of Nevada, Reno; Oregon State University; the University of Idaho; Princeton University; and Pacific Northwest National Laboratory (PNNL).

In addition to the PRBC, OHSU has proposed expansion of research and facilities aimed at developing vaccines to combat infectious disease. More information about this effort, called the Pacific Rim Vaccine Initiative, can be found at http://www.ohsu.edu/prvi.


Story Source:

The above story is based on materials provided by Oregon Health & Science University. Note: Materials may be edited for content and length.


Cite This Page:

Oregon Health & Science University. "Smallpox Vaccine Provides More Protection Than Previously Thought." ScienceDaily. ScienceDaily, 26 May 2003. <www.sciencedaily.com/releases/2003/05/030526103647.htm>.
Oregon Health & Science University. (2003, May 26). Smallpox Vaccine Provides More Protection Than Previously Thought. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2003/05/030526103647.htm
Oregon Health & Science University. "Smallpox Vaccine Provides More Protection Than Previously Thought." ScienceDaily. www.sciencedaily.com/releases/2003/05/030526103647.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
Dads-To-Be Also Experience Hormone Changes During Pregnancy

Dads-To-Be Also Experience Hormone Changes During Pregnancy

Newsy (Dec. 18, 2014) A study from University of Michigan researchers found that expectant fathers see a decrease in testosterone as the baby's birth draws near. Video provided by Newsy
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins