Doctors recommend finishing both Pfizer and Moderna doses despite study showing high single-dose efficacy

MILWAUKEE (CBS 58) -- The state hit a big milestone on Monday with one million people in Wisconsin having been fully vaccinated. As more and more people begin the vaccination process, doctors are stressing the importance of finishing the two-dose regimen for people receiving Pfizer or Moderna’s COVID-19 vaccine.

Various studies have shown just one dose of the Pfizer vaccine could have anywhere from 50-percent to more than 80-percent efficacy, but doctors say for now one shot is simply not enough.

“One shot certainly seems like it does something, but we’re just not sure where that number lands in the end,” said Dr. Jeff Pothof, chief quality officer at UW Health.

On Monday, March 29, the U.S. Centers for Disease Control and Prevention released data after studying 3,950 health care and frontline workers for more than three months. It said Pfizer or Moderna’s vaccine had an 80-percent efficacy rating two weeks after the first dose.

Still, doctors say there are not enough robust studies providing an exact amount of efficacy after just a single shot.

“What we want to avoid right now is with incomplete data, tell people that it’s okay to get one shot, only to find two months later, find out maybe it’s not okay,” Dr. Pothof adds.

Dr. Pothof says the CDC still recommends both doses for the highest efficacy of near 95-percent.

“Until we see trials that are designed specifically to look at single dose, it’s just hard to give that a green light,” he said.

“If you were to give me an option between less than 90-percent to more than 90-percent, I would take more than 90-percent any day,” said Dr. Silvia Munoz-Price, an infectious disease professor at Froedtert and Medical College of Wisconsin.

While some people may experience worse side effects than others from the vaccine, Dr. Pothof says symptoms from COVID-19 vaccinations are not life-threatening and most are easily managed by taking Tylenol or Ibuprofen.

“It’s so much better to experience those symptoms and then build immunity to COVID-19 than to not get that shot and then find yourself at a later date with COVID-19,” adds Dr. Pothof.

“COVID-19 is like playing the Russian Roulette, right? And it can make you really sick and it can kill you,” says Dr. Munoz-Price.

Dr. Pothof says it’s hard to say whether future COVID-19 booster shots to tackle new variants would end up being one or two doses, but in most cases boosters are typically a single dose.