Here's how Pfizer, Moderna, Novavax compare in race for COVID-19 vaccine

SAN FRANCISCO -- The race to develop a vaccine for the coronavirus is not only shifting into high gear. It turns out, drug companies are following different maps to find the finish line.

"The most important thing in a vaccine is the idea," says UCSF professor Dr. Jay Levy, M.D.

Levy is tracking efforts worldwide, including the roughly half-dozen domestic vaccine trials now getting underway in the United States.

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He says one of the most intriguing is by the company Moderna, which is using a new strategy known as messenger RNA or mRNA. Essentially writing a genetic script and injecting it into the patient, coaxing their bodies into creating a safe fragment of the coronavirus and triggering an immune response.

"The most interesting the messenger RNA, that's brand new," says Dr. Levy.

Drug giant Pfizer is also working with the technique. But it's not the only innovation in play. Researchers at Oxford have used a chimpanzee virus to create a so-called Trojan horse. Its job is to carry fragments of the coronavirus into the body without being detected leaving the immune system to attack them.

"And then that is your vaccine. And you immunize humans with that," says Stanford immunology professor Bali Pulendran, Ph.D.

Professor Pulendran says other companies like Novavax are using their own proprietary add-ons known as adjuvants to boost the overall effectiveness of their vaccines, while Johnson & Johnson says they're building on a vaccine technology they recently used to help fight an Ebola outbreak in Africa.

A remarkable range of strategies, unveiled in just a matter of months.

"So that has been just stunning progress," says Pulendran.

The first of U.S. backed vaccines from Moderna began phase 3 trials last month.

Others from Oxford/Astrazeneca, Johnson & Johnson, and Novavax are lined up in the chute, in a U.S. trial schedule stretching through this fall.

Ultimately, researchers are hoping more than one might be successful, offering options against a worldwide enemy, that has so far, provided very few.