A new swine flu vaccine was approved yesterday by the United States’ Food and Drug Administration (FDA). This is the first long-anticipated step, as the government looks to start mass vaccinations next month.

The vaccine is made by CSL Ltd. of Australia, Switzerland’s Novartis, France’s Sanofi-Pasteur and the U.S.-based Medimmune.

The bulk of the vaccines should start arriving on October 15, and it should be available at approximately 90,000 locations in the U.S. The Government has ordered 195 million doses, and will order more if needed.

The Western Australia state government confirmed recently that a 38-year-old Perth man is the first Australian case of swine flu that has been resistant to the popular antiviral drug Tamiflu.

The state’s department of health the man has a weakened immune system, and had initially responded to the drug but developed a resistant strain of the virus when his illness relapsed. Up to now, there are just 13 confirmed cases of Tamiflu-resistant Swine Flu (H1N1) infections around the world. It has widely been accepted that a few isolated cases of Tamiflu-resistant H1N1 pandemic flu would arise from time to time.

The man is currently in intensive care in critical condition.

Wondering how the Swine Flu virus actually works? A study that was released yesterday showed that the Swine flu virus can infect cells deeper in the lungs than seasonal flu, thus helping to increase the severity of the illness.

Influenza viruses penetrate cells by attaching themselves to molecules (called receptors) that are located on the outside of the cell wall. Seasonal virus strains typically attach themselves almost exclusively to cells that are found in the throat, nose and upper airway, thus helping to cause some of influenza’s signature symptoms – scratchy throat, runny nose, a dry cough.

The swine flu virus however sticks to a greater range of receptors than seasonal virus strains, and so it can also breach cells deep in the lungs.

The swine flu study was funded by the European Union, and published in the journal Nature Biotechnology. It basically provides the first laboratory confirmation of reports from front-line doctors that some patients with swine flu (h1n1) virus tend to suffer worse symptoms compared to those with a normal seasonal flu.

According to a recent study that was done in Chicago, Illinois (USA), the Swine flu was four times more likely to send blacks and Hispanics to the hospital than whites. This study is one of the first that looks at how the virus has affected different racial groups. Notably, it corresponds to recent unpublished information from Boston, MA, that found three out of four Bostonians who were hospitalized from swine flu were black or Hispanic.

Health officials have said the reason for the difference is probably not genetic, and that more likely, it is because blacks and Hispanics suffer disproportionately from asthma, diabetes and other health problems that make people more vulnerable to the flu. It is also not clear if a racial or ethnic difference will hold up when more complete national stats become available.

Source of information for the Chicago study – researchers looked at over 1500 lab-confirmed swine flu cases reported to the Chicago Department of Public Health from late April 2009 through late July.

After trading at a 52-week high of US$7.79 on Tuesday (September 1), Novavax Inc.’s shares relapsed yesterday, plunging to to 10.68% by the close of trading. Shares of the vaccine-maker took a hit after Oppenheimer Holdings Inc. cut its rating on Novavax stock to “perform” from “outperform”.

Prior to this unpleasant report, Novavax had been receiving positive attention for the successful mid-stage testing of its seasonal vaccine which uses virus-like particles to induce immune responses against three strains of viruses, including the H1N1 or “Swine Flu” virus.