We asked Dr. Stephen Thomas, chief of Infectious Diseases at SUNY Upstate Medical University, what we need to know about the vaccines right now and what we could learn in the coming months. Watch the video for a deeper explanation about the three vaccines currently available in the U.S. — Moderna, Pfizer/BioNTech and Johnson & Johnson. Moderna and Pfizer are messenger RNA, or mRNA vaccines and Johnson & Johnson is a viral vector vaccine. All three are designed to protect against Covid-19. According to the CDC, rather than inject the body with a weakened version of the coronavirus, these vaccines teach the body to make a protein which triggers an immune response. It’s those antibodies that our bodies produce that help keep us safe when confronted with the actual virus. Side Effects The mRNA vaccines have been administered to over 80 million people in the United States and they are safe and effective, Thomas said. Thomas was the lead principal investigator for the worldwide Pfizer/BioNTech vaccine trial. In data from the trials, Thomas noted, “The safety profile of these vaccines are all pretty similar, most people will experience some kind of pain at the site the vaccine was injected and most people say the pain is mild to moderate. Dr. Thomas also mentioned these other common side effects: • Mild to moderate headache • Mild to moderate fatigue • 30 to 40 percent of people might have muscle aches or joint pain • About ten to fifteen percent of people might develop a fever “The good news is if it’s going to happen to you, because it doesn’t happen to everyone, it happens pretty soon after you get vaccinated and once it starts it goes away within a couple of days,” Thomas said. “With Pfizer and Moderna rolling out over 80 million doses of vaccine the side effects continue to be the same as the data from the trials and we aren’t seeing any new side effects or more severe side effects,” he added. What about the variants? Work is being done in laboratories with the Moderna and Pfizer vaccines, testing people’s antibodies to see if the antibodies will neutralize the variants. Thomas said, “They are not as good at neutralizing those variants as they are against the predominant strain in the United States which is from China. But experiments are continuing and there is some concerning data there, which is why it’s important that we vaccinate as many people as possible, because it’s a race against the variants.” Thomas noted that the vaccines are still working at fifty to sixty-percent efficacy against the new variants. “Just to put it in context, the annual flu vaccine is about forty-five percent efficacious,” he said. How important is the two-dose vaccine time schedule? Thomas said it’s important to get these vaccines as close to the schedule as possible as they were tested in the trials. If a change is unavoidable, Thomas recommends delaying the second dose rather than getting it ahead of schedule. What is herd immunity and when will we have it? Herd immunity is achieved when enough of the population has become immune to a disease (generally through vaccinations) that it makes it difficult for that disease to spread. That would mean even those who are not immune would be protected. “Right now, about fifteen percent of the country has received at least one dose of vaccine, but that’s a far cry from the 70 to 80-percent that we are going to need to achieve herd immunity,” Thomas said. Thomas doesn’t think it’s going to be a vaccine supply issue, but more of a willingness for people to be vaccinated. “We’re vaccinating 2 million people a day, if that were to go to 3 million, and we have 320 million people in the country, we could achieve herd immunity by late summer.”