Here’s what you need to know about the second promising COVID-19 vaccine

A second COVID-19 vaccine has showed promising early effectiveness, but experts caution that the pandemic isn’t over yet as caseloads continue to spike.

Moderna on Monday announced its vaccine is 94.5% effective, according to early data. It’s not yet been approved for use, and its trials continue. The news comes a week after preliminary data from Pfizer’s COVID-19 vaccine trial showed 90% effectiveness in preventing infection among those who didn’t previously have the disease. Then, on Tuesday, Pfizer announced its vaccine is 95% effective and that it would ask for government approval within days.

“These could be real game changers,” says Dr. Robert Citronberg, executive medical director of infectious disease and prevention at Advocate Aurora Health. “The flu vaccine is 40-60% effective, so these are shockingly good reports on the efficacy of the vaccines. If confirmed with additional data, it’s an extraordinary scientific accomplishment. For the first time, we are seeing light at the end of the tunnel, and that’s something we’ve all been waiting for.”

But Dr. Citronberg warns that there’s still a long road ahead before we can feel safe.

“The vaccines themselves don’t do anything. We have to get people immunized for them to be effective, and that’s going to be a big challenge,” he says. “Particularly in some populations that are very skeptical about receiving vaccines, it’s going to take a big effort from the medical community to convince these people to get immunized.”

And while “the preliminary data suggests these vaccines are safe” with no “serious adverse effects,” he also notes that experts need to examine all the relevant safety data. Similarly, they’ll want to know know the duration of the vaccine’s effectiveness.

“Will immunity last a year, two years, five years or a lifetime? You’ll only know if you study people over a long period of time. Obviously we haven’t had time to do that,” Dr. Citronberg says. “But even if it lasts only a few months, there’s a real opportunity to make meaningful progress in terms of the pandemic – as long as we can get people immunized.”

Both potential vaccines use genetic material called messenger RNA technology, or mRNA, which doesn’t have true components of the virus itself. Rather, Dr. Citronberg says, it tricks your immune system into making antibodies against the virus, meaning one of the most common reasons people avoid vaccines may be alleviated.

The announcements comes as Illinois and Wisconsin each continue to set daily COVID-19 caseload records, increasing the concerns of health care experts.

“We continue to see record numbers of cases, positivity rates and hospitalizations throughout Illinois and Wisconsin, and deaths continue to rise,” Dr. Citronberg says. “We cannot let our guard down. No matter when the vaccine is released, we will need to remain vigilant in our fight against COVID-19. Masking, social distancing and handwashing remain critically important.”