The coronavirus pandemic is finally showing signs of slowing down in the U.S. as more and more Americans get vaccinated.

But there are still “two competing issues” taking place in terms of the virus and the vaccines, Dr. Jeremy Faust, an emergency medicine physician at Brigham and Women’s Hospital, told Yahoo Finance Live (video above).

“On one hand, you have vaccine equity and the fact that all around the world there are geriatric people, people who are retired, even health care workers on the front line who don’t have a vaccine yet,” he said. “And they are putting it all on the line every day, and we’re vaccinating our low-risk population here in the United States.”

On the other hand, when it comes to ending the pandemic, there are still a signifiant amount of unvaccinated Americans. In the U.S, nearly 50% of the population has received at least one dose of the vaccine, while 40% are fully vaccinated.

“We have to vaccinate as many people here as we can, and also push vaccines overseas,” Faust said. “There have been a lot of different ways to do that. People are talking about tech transfer and IP waivers. There are a lot of ways to do that. But I think the number one thing you can do is just do everything you can, and that’s all you can possibly ask.”

President Biden recently announced that the U.S. would begin sending shipments of vaccines to other countries in need, though the U.S. took heavy criticism prior to this move for focusing only on their citizens.

Moderna (MRNA) announced that they would waive the patent on its vaccines, so that it could become more easily available in other countries. The U.S. shipped a few million vaccines to Mexico and Canada, which is seeing a major surge in cases in its province of Manitoba. The outbreak there is disproportionately affecting Indigenous communities.

“It’s really hard to control this virus,” Faust said. “We all know that. And so any version that’s more contagious just means that you have to be that much more careful until the vaccine shows up in your neighborhood.”

The unvaccinated risk

Places that don’t have the vaccine are significantly more vulnerable, especially when exposed to people who are voluntarily unvaccinated.

In the U.S., 13% of Americans said they will not get the vaccine, according to an April 2021 poll from the Kaiser Family Foundation. In order to reach herd immunity, an estimated 75-80% of the population needs to be vaccinated. Certain states, especially in the Northeast, have reached the 70% milestone but other areas are significantly lagging behind.

“The idea is if we get something closer to herd immunity, then essentially on a macro level, we can say ‘well, enough people are doing the right thing that even the few bad actors within that 30% of people who have chosen not to be vaccinated or people who cannot be vaccinated for a number of reasons are unlikely to even be infected,” Faust said.

“So we really aren’t talking about herd immunity,” he continued. “But if you really stop and think about it, that’s what they’re doing. They’re trying to say ‘let’s make the numbers stack in our favor so that we don’t have to worry about a few people who may or may not be on the up and up about their vaccine status.’”

This is especially working as the U.S. approaches Memorial Day weekend, a time when many people gather for the holiday.

"The reality is, as the CDC director recently said, that the pandemic is not over and that the risk is still the same as it was at the height of the winter surge in January for those who are not vaccinated," Dr. Shad Marvasti, an associate professor at the University of Arizona's College of Medicine, said on Yahoo Finance Live recently. "Going into Memorial Day weekend, if you're not vaccinated, I would say you still have to practice the same mitigation measures of mask wearing and distancing, although that's been lifted in many parts of the country. And that's concerning to me."

The 7-day moving average of COVID-19 cases in the U.S. is 23,162, a 37% decrease from two weeks prior.

"I'm not as concerned about those who are fully vaccinated as I am about those who are unvaccinated," Marvasti said. "The reason being is that these folks who are unvaccinated, getting together, and the virus still circulating in the community creates a perfect storm for the development of new variants, which could be at some point resistant to the vaccines. Thankfully, that hasn't been the case yet, but there's no reason to believe that won't happen."

The other issue, Faust noted, is that more contagious variants can affect unvaccinated populations, especially children. Only children 12 and up have been approved for COVID-19 vaccines so far. However, 3.94 million children tested positive for the virus since the pandemic began.

“This virus absolutely hits older people in an order of magnitude worse than younger people, but younger people still do get hospitalized,” he said. “We don’t want to court that danger. And parents are really concerned about all kinds of side effects. They’re not sure whether to vaccinate. So the vaccine hesitancy or vaccine deliberation can really cost us in terms of getting back to life because if infections start roaring through a community, people get scared, even if most people are vaccinated.”

Adriana Belmonte is a reporter and editor covering politics and health care policy for Yahoo Finance. You can follow her on Twitter @adrianambells and reach her at adriana@yahoofinance.com.

READ MORE:

• An alarming number of Americans are unvaccinated despite wanting a jab

• 'Vaccinated people are exceedingly safe,' doctor stresses amid reports of breakthrough cases

• ‘We’re really in the early days’ of understanding neurological issues with COVID-19

• Read the latest financial and business news from Yahoo Finance

Follow Yahoo Finance on Twitter, Facebook, Instagram, Flipboard, LinkedIn, YouTube, and reddit