Here's What We Know About Moderna's Experimental Coronavirus Vaccine

An experimental vaccine may give some protection against the coronavirus, data from early stages of a human trial shows

NBC Universal, Inc.

An experimental coronavirus vaccine showed a “robust” immune response, Moderna announced Tuesday, producing promising data that the vaccine may give some protection against the coronavirus.

In the early stage of the Cambridge-based biotech company's human trial, all 45 patients produced antibodies after getting two shots, which scientists believe is important for building immunity.

In the trial, each participant received a 25, 100 or 250 microgram dose, with 15 people in each dose group. Participants received two doses of the potential vaccine.

Moderna is one of several companies working on a potential vaccine for COVID-19. More than 100 vaccines are under development globally, according to the World Health Organization.

Moderna Inc. on Thursday unveiled large-scale, expedited plans to begin the final stage of testing on its COVID-19 vaccine next month.

What we know about Moderna's vaccine:

  • It was generally safe and well-tolerated, with no serious side effects
  • About 54% of participants experienced mild or moderate side effects after the second vaccination
  • The most common side effects were fatigue (80%), chills (80%), headache (60%) and muscle aches (53%)
  • All 45 patients produced antibodies after getting two shots
  • The levels of antibodies in patients were four times higher than in recovered COVID-19 patients
  • It remains unclear how long immune response lasts
  • Participants will be followed for one year after the second vaccination
Peter Pitts, the former FDA Associate Commissioner, said industry, academia and government are working together to make an effective coronavirus vaccine available by early 2021. But the rollout is expected to be complicated, with more than one vaccine likely available and questions about which groups should be prioritized to get the vaccine first.

Moderna’s experimental vaccine contains genetic material called messenger RNA, or mRNA. The mRNA is a genetic code that tells cells what to build — in this case, an antigen that may induce an immune response to the virus. It became the first candidate to enter a phase 1 human trial in March.

Scientists are still learning about key aspects of the virus, including how immune systems respond once a person is exposed. The answers, they say, may have important implications for vaccine development, including how quickly it can be deployed to the public.

The U.S. is aiming to deliver 300 million doses of a vaccine for COVID-19 by early 2021. 

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