By Jason Gale and John Lauerman
May 14 (Bloomberg) — Sanofi Aventis SA, GlaxoSmithKline Plc and other drugmakers may start plans to make a vaccine for the swine flu virus that health experts say causes higher rates of pneumonia and other complications than the seasonal strain.

Drug regulators and scientists will confer today at the World Health Organization with company officials to consider whether and when to begin the three-to-six-month process of making shots to protect people against swine flu, known as A/H1N1.

Pharmaceutical companies have been waiting for data on the flu’s severity to determine how soon to begin producing an inoculation. A study in the May 11 edition of the journal Science found that 4 of every 1,000 people infected with the bug in Mexico by late April died, and the WHO said the virus “appears to be more contagious” than seasonal flu.

“It’s almost a no-brainer,” Robert Webster, a flu expert at St. Jude Children’s Research Hospital in Memphis, Tennessee, said yesterday in a telephone interview. “It makes sense for vaccine companies to get all their ducks lined up, as it were, to make a vaccine for this new strain.”

The Geneva-based WHO says the virus that has spread to 33 countries may touch off the first flu pandemic since 1968 and is more dangerous than the germs that cause seasonal epidemics, which kill 250,000 to 500,000 people each year. The Science study estimates the virus is as severe as the 1957 Asian flu pandemic strain that caused about 2 million deaths.