Malaria is one tough cookie. There are prophylaxes to prevent infection and other drugs available to treat the infection, but an effective vaccine has largely eluded drugmakers. The lack of an effective vaccine leads to close to 900,000 deaths a year. That's the population of the state of Delaware.

Rather than fight the microorganism alone, Crucell (Nasdaq: CRXL) and GlaxoSmithKline (NYSE: GSK) decided to team up. A few years ago, the companies announced that they'd test their individual vaccines against one of the parasites that causes malaria to see if combining them elicited a stronger immune response. The results were good enough that the companies announced today that they're extending their partnership and advancing the combination product into the clinic.

Combining treatments to increase efficacy isn't anything new. Pfizer (NYSE: PFE) and Glaxo have teamed up to develop combo drugs to fight HIV as have Johnson & Johnson (NYSE: JNJ) and Gilead Sciences (Nasdaq: GILD). Merck (NYSE: MRK) and AstraZeneca (NYSE: AZN) have decided to test their individually developed cancer drug candidates together.

Unlike HIV and cancer, though, the moneymaking opportunity for Crucell and Glaxo is limited because malaria isn't a big problem for countries that can afford high drug prices. The duo will likely have to find a nonprofit or government entity to pony up some cash to fund the large phase 3 trial.

Developing a malaria vaccine won't get the companies rich, but cutting into the 900,000 annual deaths should give them some positive publicity. Considering the beating the industry has taken due to high health-care costs, investors should welcome the potential public relations bonus.

Pfizer is a Motley Fool Inside Value selection. Johnson & Johnson is an Income Investor selection and Motley Fool Options recommended buying calls on the stock. Try any of our Foolish newsletters today, free for 30 days

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool owns shares of GlaxoSmithKline and has a disclosure policy.