If you ask biodefense experts to name two diseases that prevent them from sleeping at night, there's a good chance they mention smallpox and anthrax. Both are highly lethal, and current vaccines have major problems. Now researchers have found a way to target both the threats both :. A candidate vaccine that protects against both diseases and seems to work better than existing preventatives
The vaccine against smallpox, a terrible viral disease that has killed 30% of its victims before it was eradicated in 1970 is very effective in a single dose. But the vaccine is a live virus itself, called vaccinia, which can cause serious side effects such as brain and heart inflammation, sometimes leading to death. It is not recommended for different risk groups such as patients with eczema and immunocompromised which together form a quarter of the population. Officially, only two laboratories in the United States and Russia still have major , the smallpox virus smallpox, but many worry about hidden stocks elsewhere.
The vaccine against anthrax is also problematic. Composed of bits of a protein called protective antigen (PA) -which are harvested from the anthrax bacteria, Bacillus anthracis- vaccine is a heavy set of five or six blows on 18 months requires annual boosters. It is also not very stable and has a shelf life of about 4 years, which makes the storage for expensive emergencies. And although the vaccine against smallpox is fast enough to provide protection, even when administered several days after exposure to the pathogen, the laboratory data suggest that the vaccine against anthrax does not. (Because anthrax is rare, there have never had the opportunity to test.)
Improving on these so-so shots has never been a priority until the first Gulf war, 9/11 and the anthrax attacks in 01 propelled the risk of bioterrorism and bioterrorism in the political agenda. Now many researchers are trying to develop smallpox vaccines softer and easier to use, more effective anthrax.
During the last decade, researchers led by Liyanage Perera of the National Cancer Institute have developed what they claim is a vaccine against smallpox safer. They did this by equipping the vaccinia virus with a gene that codes for interleukin-15 (IL-15), a signal molecule which stimulates the immune system and helps clear the virus more quickly from the body while triggering a strong reaction. In a recent article in Vaccine , the team showed that the new vaccine against smallpox did not kill immunocompromised mice as vaccinia standard is; and monkeys, it offered a long-term protection of monkeypox, the best animal model for smallpox
For the current study, the researchers went further :. They also sewn into the skeleton of vaccinia gene encoding a PA subunit of the protein in the vaccine against the current anthrax. In an article published online today in the Proceedings of the National Academy of Sciences ( PNAS ), the team shows that two doses of vaccine given 28 days resulting in protection rabbits out of another lethal dose of spores of anthrax inhalation. In other mouse studies, the vaccine not only generated more antibodies against PA that the conventional vaccine, but also made faster, probably because IL-15 stimulating effects. That means there could be more useful after an anthrax attack the current vaccine, the writing team. And unlike the existing vaccine against anthrax, it can be lyophilized and stored probably for decades.
In the document PNAS , the team has not said whether the vaccine also protects against smallpox and its ilk, but additional studies suggest it does, said Perera .
The vaccine is still far from being approved, says Nir Paran, who studies poxviruses to the Israel Institute of Biological Research in Ness Ziona-. Still, he said, "It is an interesting document that addresses several important issues."
But Les Baillie, a researcher of anthrax at the University of Cardiff in the UK, is not so sure the vaccine will be very helpful after a bioterrorism attack. Even with a vaccine that is faster is vaccinate large numbers of people quickly would be a huge logistical challenge, he said. in addition, a dual vaccine might not make sense in this situation: "If you have an anthrax epidemic, why would you also to vaccinate thousands of people against smallpox?"
The vaccine may be more useful before exposure, Baillie said, for example, for military personnel and first responders who are most likely to come into contact with one of the agents. "If you can take care of all the dirty tricks with a jab, it's a huge logistical advantage."
0 Komentar