ROCHESTER, N.Y. (WROC) — With recent chatter over the Johnson & Johnson vaccine going on state-wide pause, you may be hearing terms “mRNA” and “Adenovirus” thrown around.

To put it simply, medical experts have been comparing Johnson & Johnson to Astrazeneca, another vaccine for COVID-19 that was suspended in some countries for reported blood clot cases. The two are getting compared not only for having the same blood clot reports, but they also use the same ingredient that differs from what Pfizer and Moderna use.

Dr. Ramil Sapinoro, associate professor of Pharmeceutical Sciences with St. John Fisher College says all these COVID vaccines perform the same task, just with this one differing ingredient.

“The Pfizer and Moderna vaccines main component is mRNA. That stands for messenger RNA, it is something our cells already produce naturally, it is instructions for how to make a protein,” Dr. Sapinoro said.

He says it educates our cells on how to make a piece of a “spike” protein. The CDC defines this as a protein found on the surface of the virus that causes COVID-19. That way when the actual virus is introduced in the body, the body will already have developed some kind of an immune response.

With Johnson & Johnson and Astrazeneca, it’s the same method of delivering instructions for our body to make that immune response, but using another tool to do it. The tool is called the adenovirus.

“It’s a harmless cold virus that many of us get every year probably, we are just using that as a delivery system to get the instructions for the spike protein into our cells,” says Dr. Sapinoro.

Dr. David Topham is a professor of microbiology and immunology at the University of Rochester Medical Center. He says there could be something about the adenovirus that results in blood clots, but that it’s too soon to draw any immediate conclusions.

“Data is not strong yet … what I think will happen is they take a close look at the subjects that had those adverse reactions, and do a number of tests to find out, genetic tests, blood tests to find out if there is some underlying cause or risk factor that we weren’t aware of before,” he said.

In the meantime, while we wait for answers, both Dr. Topham and Dr. Sapinoro say a lot of the conversation is weighing risk factors. But the optics do matter – and we need to be able to get to the bottom of any severe side effects first, they say.

Click here for more on local medical responses to the recent Johnson & Johnson news.