Johnson & Johnson says it's ready to begin shipping doses as early as today.By Chris Hoffman

PITTSBURGH (KDKA) — The FDA is giving the green light to a third COVID-19 vaccine.

This one is being called a possible game changer.

The new shot comes from Johnson & Johnson, and a rapid rollout for the vaccine is imminent.

Johnson & Johnson says it’s ready to begin shipping doses as early as today.

Four million doses could be shipped out this week.

Twenty million doses are anticipated to be shipped by the end of March and 200 million doses by June.

The main difference between this vaccine and the ones from Pfizer and Moderna is that this one only requires one dose and doesn’t require special storage conditions.

The FDA has approved this vaccine for people over the age of 18.

The FDA confirms that this vaccine is slightly less effective than the Moderna and Pfizer shots overall — but showed 85% efficacy against severe illness and complete protection against COVID-19 deaths 28 days after getting the shot.

Local health officials say they are excited about this development.

“This new vaccine is done by putting the gene for the spike protein inside of virus that causes the common cold, so it’s a weakened virus that causes the common cold. so it can cause the common cold, but it delivers the instructions to make the spike protein,” said Dr. Lee Harrison, Professor of Medicine and Epidemiology at the University of Pittsburgh.

Later this afternoon, a CDC advisory committee will set and vote on new guidelines for the new single-dose vaccine.

The FDA says the most common side effects in their study of the Johnson & Johnson vaccine included pain where the dose was injected, headaches, muscle pain, and fatigue, but these are similar to the side effects from Moderna and Pfizer’s vaccines.