Novavax is late to the vaccine party. Three other vaccines have already been approved for emergency use. The availability of Novavax fills a gap but it’s not clear how big that gap is.

The current vaccines from Pfizer, Moderna and J&J are based on nucleic acid technology. The first two vaccines use mRNA to program your own cells to manufacture the Covid spike protein that your immune system then recognizes and reacts to. The J&J vaccine works in a similar way using a deactivated virus to deliver its payload to your immune system cells.

Novavax is more conventional. It’s the product of an established technology that creates the Covid spike protein in the lab. That purified protein becomes the vaccine that your immune system reacts to after it is injected. Protein-based vaccines have been the mainstay of vaccine technology for decades. While the Novavax technology is modern, the final product you receive is similar to vaccines for other viral illnesses like influenza, chickenpox, measles, etc.

Novavax is a series of two vaccines for persons who have not been previously vaccinated. It is not currently approved for use as a booster, however.

So Novavax may be acceptable to persons who are hesitant to take the current RNA vaccines. Given that anti-vaccine attitudes have emerged during Covid, few experts are certain whether Novavax will be enthusiastically received by those who have declined vaccination so far.