Older adults, healthcare workers and immunocompromised individuals were first in line to receive the COVID-19 vaccine late last year, and now, the progression is reaching a much younger demographic.

Recently, the Food and Drug Administration (FDA) approved the Johnson & Johnson vaccine booster shot for all adults and the Centers for Disease Control and Prevention (CDC) approved the Pfizer-BioNTech COVID-19 vaccine for children ages 5 to 11. This age group will receive a smaller dosage: about one third of the typical vaccine dose.

“Even though the rate of disease of those children is relatively low compared to older people, it's still not insignificant,” Shin said. “It is a risk. In the most recent Delta surge ... COVID-19 was (one of the) highest leading causes of death for children ages 5 to 11. We can eliminate that and protect children. The vaccines will be able to do that.”

Approximately two million children in the U.S. contracted COVID-19 since the beginning of the pandemic, and now, millions of children are set to receive their vaccines this week.

The Moderna and Pfizer COVID-19 booster shots are both FDA-approved to administer six months after the second dose for those 65 and older or at high risk for COVID-19. In contrast, the Johnson & Johnson booster shot has been approved for individuals ages 18 and older only two months after receiving the single-dose vaccine.

Sanghyuk Shin, an epidemiologist from the University of California, Irvine, said these recommendations are based on new scientific evidence.

“We’ve seen very little drop in the effectiveness of (the Moderna and Pfizer) vaccines in preventing hospitalizations and death,” Shin said. “The reason why the (Johnson & Johnson) second dose is now being recommended is that studies have shown that, while the one-dose vaccine does prevent infection, a second dose would significantly improve the protection among the people who are vaccinated, regardless of their underlying needs.” 

Franny Hill, a sophomore broadcast journalism and documentary major at Chapman University, was vaccinated back in March 2021. Though she said Johnson & Johnson was the only option available to her at the time, she admitted the single-dose was convenient, since she didn’t have a car. 

Now, Hill is more than happy to get a booster shot to protect herself and those around her, especially after she contracted COVID-19 in September. However, Hill said she is considering utilizing the “mix-and-match” method — meaning to receive a booster shot from a COVID-19 vaccine different than she originally received — and choosing the Moderna booster shot.

“I will 100% get my booster shot when I can,” Hill said. “I’d prefer to get Moderna because my mom got Moderna — she’s a school administrator who’s been exposed to COVID several times, and her vaccine has held up really well … Everyone I know who had breakthrough cases have been (Johnson & Johnson) or Pfizer. I trust them all, but I will say, after my breakthrough case, I was very annoyed. So, I think I would prefer Moderna.”

Further, experts have advised that switching up booster shot manufacturers may be beneficial, especially for those who received Johnson & Johnson, a non-mRNA vaccine.

Early studies have shown the mix-and-match strategy is not only both safe and effective, but that mixing vaccines also can sometimes create a broader, more potent response than getting multiple doses of a single vaccine.

While the mixing-and-matching has been approved by the FDA, Shin said the method isn’t necessarily better.

“There’s multiple studies that show regardless of which vaccine you get — if you get the same vaccine or different vaccine as your second dose — you still get a very robust immune protection, and vaccine effectiveness seems to be very strong,” Shin said.

Some immunocompromised individuals may have to receive a fourth vaccine dose, according to new Center for Disease Control and Prevention (CDC) guidelines.

“The evidence I've seen suggests there are going to be some people that are so immunocompromised that even a third dose isn't going to protect them,” Shin said. “There are some people who have not been responsive to vaccines, because vaccines boost your natural immunity. If your natural immune system is depleted and not fully functioning, you may not respond to vaccines, regardless of how many doses you get.”

Jerika Lam, Chapman’s viral infection specialist, said the most important factor to move past the pandemic is getting unvaccinated people to get their shots.

“All of us want to return to some sense of normalcy, and I think the vaccines — as we know now —  have helped tremendously to reduce the ongoing spread of COVID-19 and also reduce hospitalizations and deaths,” Lam said. “We know vaccines work.”