Researchers at UW-Madison have discovered a new drug that may prevent human influenza infections—including avian influenza strains that are capable of launching a flu pandemic.
The chemical compound is still years away from pharmacy shelves, but shows great promise in combating the flu, which claims 40,000 lives every year in the United States.
UW-Madison medical microbiology and immunology professor Curtis Brandt, who normally works with herpes viruses, conducted the groundbreaking research with UW-Madison medical microbiology and immunology assistant professor Stacy Schultz-Cherry—a specialist in influenza viruses.
Brandt said the key compound, a protein particle that was discovered in his lab, is the first chemical researchers have successfully used to prevent viruses from entering cells and causing infection. Existing antiviral compounds such as Amantadine and Tamiflu ameliorate infections but don't prevent them.
In Brandt and Schultz-Cherry's study, the new compound prevented strains of human influenza and avian influenza from infecting both cell cultures and animals.
Brandt said during the next phase of research, estimated to take four to five years, the research team will refine the compound's formulation and develop a reliable manufacturing process. Researchers will also focus on understanding how the compound works in the body and will identify any toxic effects. Clinical trials, lasting from three to five years, will follow.
Both Brandt and Schultz-Cherry think it is important to find new antiviral drugs that can combat influenza.
""This gives us another tool,"" Schultz-Cherry said. ""We're quickly losing our antiviral treatments [to resistant strains].""
Brandt said resistance to existing antiviral medication such as Rimantadine and Amantadine is common among flu strains circulating in the United States.
There is also evidence of Tamiflu resistance to avian flu strains in Southeast Asia.
""The more antivirals that you have, the better chance you have that you can stop [influenza],"" Brandt said.
While Schultz-Cherry and Brandt continue their antiviral research, the National Institute of Allergy and Infectious Disease is testing avian flu vaccines for humans. According to its website, NIAID recently completed successful human clinical trials of an H5N1 avian flu vaccine among 18 to 64 year-old subjects.
H5N1, named for the particular features of the virus, is considered to be the most dangerous strain of avian flu currently circulating.
An NIAID report found that the vaccine induced sufficient immunity to prevent infection from the H5N1 flu virus. Additional clinical trials to test different vaccination formulations, dosages and age groups are ongoing.
Brandt said vaccines alone are not enough, however.
""If we have one of these [avian] pandemic strains pop up or one of these other pandemic strains, it generally takes nine months once we detect the virus before we can have vaccine available for distribution. So, what are we going to do in those nine months?"" Brandt said.
""You saw what happened with SARS—how quickly that spread out from southern China. So, unless we get a lot better at vaccinology for influenza, we're going to need antivirals as the front line of defense until you can get a vaccine preparation made,"" he continued.
Brandt also said vaccines are not 100 percent effective at inducing immunity in the elderly and the very young.
""So, we still need effective antivirals for those kinds of circumstances,"" Brandt said. ""I think it's sort of disingenuous to pit one [anti-flu tool] against the other.""
Craig Roberts, epidemiologist at University Health Services, suggests all students—especially those with asthma, diabetes, immune problems and other risk factors—should receive the standard influenza vaccine. Although the vaccine UHS provides does not cover any of the several avian strains, it protects against the most common strains of influenza found in the United States.
The vaccination, available since Oct. 23, is free and available on a walk-in basis. Roberts said vaccination is 80 to 90 percent effective against the strains covered by the vaccine.
Roberts also suggested a more homely means of prevention: regular hand-washing.
According to Roberts, a lot of people get infected by colds and flu not just by aerosol exposure to someone's cough or sneeze, but also from their hands.
""We tend to touch our faces constantly so regular hand-washing is always important for prevention of all of these things, not just ... influenza,"" Roberts said.
