Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

OHSU researchers publish final results of groundbreaking smallpox vaccination study

18.08.2003


Study results show smallpox death toll may be lower than expected in the event of an outbreak and one vaccination may be as effective as many



Final results of a smallpox vaccine study conducted by researchers at Oregon Health & Science University show America’s preparedness for a smallpox outbreak may be greater than initially thought. The research shows 90 percent of those vaccinated 25 to 75 years ago maintain a substantial level of immunity. In addition, researchers concluded that in the long term, repeated vaccinations do not result in a higher level of disease protection. The research project is the largest of its kind ever conducted. The study is printed in the September edition of Nature Medicine.

"Previously, it had been widely accepted that smallpox virus effectiveness lasts only 3 to 5 years," said study principal investigator Mark Slifka, Ph.D., a scientist at the OHSU Vaccine and Gene Therapy Institute. "This research shows that significant immunity levels last for many decades, perhaps throughout a person’s entire life. It also shows that repeated vaccinations provide a short-term boost in immunity but, over time, do not create a sustained higher level of protection compared to those persons vaccinated only once."


To conduct the research, OHSU enlisted the help of 332 study participants. Of this larger group, 306 participants had received at least one vaccination within their lifetime, some had undergone as many as 14 inoculations. The timing of vaccinations also varied among study volunteers. Some participants had been vaccinated as recently as one month prior to testing and as long ago as 75 years. The remaining 26 participants in the study had never received a smallpox vaccination in their lifetime and served as control subjects. The study group was very diverse; volunteers included those vaccinated in 43 states and 34 foreign countries.

"Some of our study participants had received repeated vaccinations. In one case, a person who at one time worked in a smallpox hospital had been vaccinated 14 times over their lifetime ," explained Slifka. "While many would assume this person would have a much higher level of immunity than a person only immunized once, we found this to be not necessarily the case."

Researchers also made key discoveries about long-term immune system responses following inoculation. They found that one component of the immune system retained memory of how to fight smallpox for a much longer period than another immune system component. One form of immunity is linked to levels of antibody produced in the body in response to the vaccine. In study participants, these antibody levels remained relatively stable up to 75 years post-vaccination. The second form of immunity is antiviral T-cells programmed by the vaccine to attack the smallpox virus. In study participants, antiviral T-cell levels declined slowly over time with a half-life of approximately 8 to 15 years.

"We found that while antibody immunity can last throughout a person’s lifetime, T-cell immunity declines slowly over time," explained Slifka. "This may help explain curious findings in previously gathered data about vaccinated patients who became infected with smallpox at a later time."

Historical data suggests that immunity against lethal smallpox infection can be maintained for many years after vaccination. However, this same data also shows that the level of disease severity increases with the length of time between vaccination and infection – in other words more severe cases occur in infected patients vaccinated many years ago compared to infected patients vaccinated more recently. While Slifka says it’s difficult at this point to state whether antibody or T-cell levels correspond to death and severity rates, the possibility of a connection exists.

The next step for Slifka and his colleagues is to track immune system responses for those recently vaccinated, the designated "first responders" in the case of a new outbreak. By studying these individuals, scientists will obtain a better understanding of how their immune systems respond over time and how varied the vaccine responses can be.

Slifka and his colleagues wish to thank those who assisted in gathering this research data, including the many local study volunteers, Washington County Public Health Officer Jay Kravitz, M.D., Clackamas County Health Officer Alan Melnick, M.D., and Multnomah County Health Officer Gary Oxman, M.D.

Jim Newman | EurekAlert!
Further information:
http://www.ohsu.edu/

More articles from Health and Medicine:

nachricht Routing gene therapy directly into the brain
07.12.2017 | Boston Children's Hospital

nachricht New Hope for Cancer Therapies: Targeted Monitoring may help Improve Tumor Treatment
01.12.2017 | Berliner Institut für Gesundheitsforschung / Berlin Institute of Health (BIH)

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Long-lived storage of a photonic qubit for worldwide teleportation

12.12.2017 | Physics and Astronomy

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>