Moderna says its COVID-19 vaccine highly effective in late trial

Side effects include fatigue, muscle aches and injection-site pain

Drugmaker Moderna says early analysis from its phase three trials show its COVID-19 vaccine to be 94.5 percent effective at preventing infection.

A week ago, competitor Pfizer announced its own vaccine was more than 90 percent effective.

The strong results come as a surprise. Scientists have been warning for months a COVID-19 vaccine may be only as good as flu shots, which are about 50% effective.

The main side effects were fatigue, muscle aches and injection-site pain after the vaccine’s second dose, at rates characterized as more common than with flu shots but on par with others such as shingles vaccine.

Moderna acknowledges the protection rate might change as more COVID-19 infections are detected and added to the calculations. It’s also too soon to know how long protection lasts.

Neither Moderna’s nor Pfizer’s vaccines are made with the coronavirus itself, meaning there’s no chance anyone could catch it from the shots. Instead, the vaccine contains a piece of genetic code that trains the immune system to recognize the spiked protein on the surface of the virus.

Moderna’s vaccine, created with the U.S National Institutes of Health, is being studied in 30,000 volunteers.