WHO: Swine Flu Virus 'Unstoppable'The World Health Organization (WHO) says drug makers can go ahead and manufacture vaccines against the pandemic influenza strain, but says the new H1N1 swine flu virus is "unstoppable." WHO says healthcare workers should be the first group to get vaccinated.
WHO's director of the Initiative for Vaccine Research, Dr Marie-Paule Kieny says the Strategy Advisory Group of Experts (SAGE, the highest level of advisory bodies in WHO on immunization matters) met last week. Members were updated about the epidemiological status and the clinical status of H1N1, as well as expected vaccine availability.
Kieny says the committee recognized "the H1N1 pandemic is unstoppable and therefore that all countries will need to have access to vaccines." She adds that committee also recognized different countries have different epidemiological and other situations. "Therefore the countries themselves will have to take decisions that are best adapted to their own national situation, but in terms of giving indicative guidance SAGE recommended first that healthcare workers should be immunized in all countries in order to maintain functional health systems as the pandemic evolves," Kieny says. (Full transcript of press conference).
Recent reports show the new virus attacks people differently than seasonal flu and affects younger people, the severely obese and seemingly healthy adults. The virus also causes pneumonia deep in the lungs.
Seasonal influenza itself is deadly every year, killing anywhere from 250,000 to 500,000 worldwide. Most of those deaths are the elderly or those with chronic disease or suppressed immune systems.
People born before 1920 appear to have some added immunity to the new H1N1 virus. The new virus is a mixture of two swine flu viruses; one also contains genetic material from humans and birds. The virus is a distant relative of the H1N1 virus that was behind the 1918 pandemic that killed up to 100 million people in three different waves.
A study published in the journal Nature on Monday (link)
confirms the blood of people born before 1920 carries antibodies to the 1918 strain, suggesting their immune systems remember a childhood infection. The study done by Dr. Yoshihiro Kawaoka also supports other studies that show the new H1N1 strain does not stay in the nose and throat, as do most seasonal viruses.
"The H1N1 virus replicates significantly better in the lungs," Kawaoka said. Other studies have also shown it causes gastrointestinal effects and it targets people not usually thought of as being at high risk, including obese people. Kieny says it isn't clear if obese people may have undiagnosed health problems that make them more liable to fall victim, or if being obese is in itself a risk.
The CDC estimates at least a million people are infected in the United States alone, and clinics everywhere are advised not to test each and every patient, so keeping an accurate count of cases will be impossible. The United States has documented 211 deaths and WHO counted 429 early last week.
Kieny says WHO would also work to get better viruses to make vaccines. She notes the strains distributed so far did not grow very well in chicken eggs, which are used to incubate all flu vaccines. There is one exception: AstraZenaca's MedImmune makes a live virus vaccine that is dispensed by squirting into the nose. This is easier to produce, Kieny notes. Kieny says the seasonal H3N2 strain was also very active now in the southern hemisphere's winter. Last week, Argentine banks closed on Friday along with other businesses for a long weekend to stem the spread of the virus in that country.