Children's Hospital Colorado

COVID-19 Vaccine Approvals: What Comes Next

Physician giving a vaccine shot to a patient.

This page was updated Feb. 24, 2021. Due to the evolving nature of the pandemic, recommendations can change quickly. Please follow all health and safety guidelines set by your local public health authorities. Reference the Centers for Disease Control and Prevention (CDC) and Colorado Department of Public Health and Environment (CDPHE) for ongoing updates on COVID-19.

When will I be able to get the COVID-19 vaccine? When will it be available for kids? How do we know the vaccines are safe? Our pediatric infectious disease expert Sean O’Leary, MD, MPH breaks down the latest on the effort to produce safe and effective coronavirus vaccines.

Which COVID-19 vaccines are approved and when can I get them?

In December 2020, the U.S. Food and Drug Administration approved two vaccines for COVID-19 for emergency use: First one from drug-makers Pfizer and BioNTech, and another from the drug-maker Moderna. Both vaccines are based on a technology known as mRNA, and both were shown in clinical trials to be better than 90% effective. Both also require two doses, an initial shot and a booster 3 to 4 weeks later, to be fully effective.

The Centers for Disease Control and Prevention has specific recommendations for who should get the vaccine and in what order. However, the CDC is a federal agency and actual rollouts have been left up to individual states, which have faced challenging and complicated logistics. President Joe Biden has stated his administration’s goal is to administer a million vaccine doses a day.

Many people at especially high risk — healthcare workers and residents of nursing homes — have been vaccinated.

In Colorado, we’re in Phase 1. Some front-line workers such as teachers and police officers, as well as adults older than 65, began receiving the vaccines February 8. Next are other front-line essential workers and people age 16 to 65 with two or more high-risk conditions, as defined by CDPHE. Here at Children's Colorado, leaders are preparing a plan for vaccinating patients as they become eligible according to the State's guidelines.

What about the other vaccines I’ve heard about?

On February 4, 2021, the pharmaceutical company Johnson & Johnson applied for FDA emergency authorization for its COVID-19 vaccine. It’s expected to be approved, but it’s not clear how long the FDA might take to approve it or when it might become publicly available. It could be as early as late February or early March.

That’s a promising development. Clinical trials showed the Johnson & Johnson vaccine to be 66% effective worldwide, although that figure increased to 72% in the U.S. It’s important to remember that the term “effective” refers to the vaccines’ ability to prevent transmission of the virus from one person to another. But even in cases where the virus was transmitted, the vaccine still protected against severe infection and death. That’s great news. More great news: unlike the Moderna and Pfizer vaccines, the Johnson & Johnson vaccine can be stored at normal temperatures and only requires one dose, rather than the two doses the Moderna and Pfizer vaccines require.

A vaccine from the drug-maker AstraZeneca, which was funded in part by the U.S., was recently approved in the United Kingdom, and a vaccine from the drug-maker Novavax just entered a “rolling review” of its ongoing trial data with the FDA, which could speed up the approval process when those trials wrap up.

There’s good reason to hope all three might be approved. More vaccines would speed up the rollout for everyone.

When might my kids be vaccinated?

Children younger than 16, especially children without any underlying conditions, are not likely to get the vaccine for several months. There are two reasons for that.

One is that kids are at far lower risk for serious complications of COVID-19 than adults, particularly older adults. Many kids who get COVID-19 never even have symptoms.

Additionally, kids’ bodies are different, and they may react differently to a vaccine than adults do. Pfizer’s trials included kids as young as 12, but Moderna’s trials only involved adults, although Moderna is currently enrolling adolescents as young as 12 in pediatric trials. Studies that involve children younger than 12 are in the planning stages at this point, and Dr. O’Leary encourages families to be patient while waiting for a safe and effective vaccine for kids. While we wait, parents should make sure that the whole family has received a flu shot and is taking all precautions to prevent COVID-19, including masks and social distancing.

How we got here

Operation Warp Speed and the successful push for a safe and effective vaccine

Vaccines are a risky proposition for pharmaceutical companies. Only about one in 10 vaccines in development is likely to produce a viable result, and they take a long time to develop. The quickest before COVID-19 took about four years. Most take closer to 10 or 15.

Operation Warp Speed was the U.S. Department of Health and Human Service’s attempt to shatter that timeline, basically by paying six different pharmaceutical companies to give it their best shot — ideally bringing a vaccine to market within a year.

“It’s unprecedented,” says Dr. O’Leary.

A pediatric infectious disease specialist at Children’s Hospital Colorado, Dr. O’Leary has himself played an outsized role in the scientific community’s response to the pandemic, as a representative of the American Academy of Pediatrics. He also played a role in CDC committee that approved and made recommendations on the current available vaccines.

How did the vaccine development happen so fast?

It happened fast for two basic reasons. One was funding. Vaccines cost a lot of money to develop, and because so many of them fail, drug-makers take on a lot of risk developing them. Operation Warp Speed absorbed that risk by paying pharmaceutical companies up front. The U.S. government spent tens of billions of dollars in the hope of helping produce at least one viable vaccine, and hopefully more. The effort paid off.

The other reason was efficiency. It takes a lot of people and organizations to develop and produce a vaccine, and typically, the process involves a lot of waiting: for funding, for supplies, for review processes, and so on. In Operation Warp Speed, the whole process was streamlined.

A drug company would also typically wait to see if their vaccine was approved and recommended before beginning to manufacture. Operation Warp Speed, however, paid pharma companies to manufacture their vaccines before it was known if they’d work. So once they were approved, they were ready to go immediately. Even then, doses are in short supply. But as long as the timeline currently is, it would be a lot longer if Pfizer and Moderna were only starting to ramp up manufacturing now.

To better understand that timeline, it helps to understand what’s happened so far.

What it takes to develop a vaccine

At the most basic level, a virus is really just a tiny wad of genetic code. It gets into the body, attaches to cells and essentially highjacks their mechanisms to reproduce itself. In response, ideally, the immune system makes antibodies that kill the virus off. But in the meantime, the virus can do a lot of damage.

The idea of a vaccine is to prevent the virus from infecting the body in the first place. Vaccines more or less train the body to kill a virus as soon as it comes along, before it does. It’s a complicated process that typically starts with understanding as much as possible about how, specifically, the virus works in bodies. How does it get into cells? How does the immune system react to it?

In the case of COVID-19, there’s a lot scientists still haven’t figured out. For example, multisystem inflammatory syndrome in children, or MIS-C, a dangerous condition that COVID-19 causes in a small number of kids, is probably related to immune response. But scientists don’t know exactly how or why.

On the other hand, there is also a lot that scientists do understand about this virus, and we’re learning more every day. For example, we knew the genetic code of this virus over a year ago, before many people had even heard of COVID-19. The speed of development, says Dr. O’Leary, speaks to the decades of research on vaccines in general and on coronaviruses specifically that have led us to this moment.

Testing a vaccine on humans

Viral infection is a molecular process, so once a pharmaceutical developer has a handle on the chemistry, the next step is to test the biology in animals. Both those steps generally take years. But if a vaccine, after much testing, does look safe and effective, eventually it makes the leap to testing in humans.

Those tests are called clinical trials, and they happen in three phases.

Phase one

The big question in phase one is, “Is it safe?” Phase one trials typically involve a small group of people. If the treatment is shown to have harmful effects, the testing ends and everyone goes back to the drawing board.

Phase two

Phase two often involves a randomized control trial, where participants are usually divided into two groups: one gets the treatment being tested; another gets a placebo, or dummy drug. In this phase, researchers are building a better understanding of the treatment’s safety, as well as how and if it works. In the case of vaccines, one of the big questions in phase two trials is if the vaccine generates enough immune response to be effective.

Phase three

The final phase involves the largest group of people, often in the thousands or tens of thousands. This phase seeks to answer, “How effective is it, and how does it work best?” Researchers study how the drug works on people of different ages and medical histories, comparing different doses and frequencies. In the case of a COVID-19 vaccine, the U.S. Food and Drug Administration has stated it would approve a vaccine that protects against the virus in at least 50% of people who get it. As with earlier phases, safety remains of paramount concern.

How does a new vaccine get approved?

The FDA: approval

If a potential treatment is shown through clinical trials to be safe and effective, the pharmaceutical company then submits all their trial data to the Federal Drug Administration, or FDA. The FDA reviews the data and decides whether to approve the treatment — meaning it decides whether the company can sell the treatment to the public. This process alone typically takes at least a year.

In addition to internal review by staff at the FDA, the FDA also has an external group of experts called the Vaccines and Related Biological Products Advisory Committee, or VRBPAC for short. The committee consists of 15 outside experts in virology, epidemiology, biostatistics, microbiology and about a dozen other related disciplines. All of its members are thoroughly vetted for potential conflicts of interest and are not beholden to political interests. In general, without the VRBPAC approval, the FDA doesn’t approve.

The CDC: recommendation

If the FDA approves of a new vaccine, it then goes to the CDC, which decides whether to recommend it in the U.S., and for whom. This step is an important one for vaccines, since healthcare plans are required to cover vaccines with no deductible under the Affordable Care Act. That coverage doesn’t happen without a CDC recommendation.

Like the FDA, the CDC has a review process conducted by a panel of vetted outside experts removed from political pressure, this one called the Advisory Committee on Immunization Practices, or ACIP. That’s the one Dr. O’Leary is a part of, as a representative of the American Academy of Pediatrics and the Pediatric Infectious Diseases Society. Their meetings are free and open to the public, if you’re so inclined.

The Pfizer and Moderna vaccines have already gone through that entire rigorous process — and any other vaccines that might be approved in the future will go through it too.

How do mRNA vaccines work?

Both Pfizer’s and Moderna’s vaccines employ a technology called messenger RNA. Where traditional vaccines have generally used inactivated parts of the infectious virus to prime the immune system to respond to it, messenger RNA, or mRNA, actually tells cells what to build inside themselves. The vaccination works essentially by introducing a bit of code that tells cells how to protect themselves against a virus.

The advantage of mRNA vaccines is that they’re faster and cheaper to produce. And since they aren’t made using infectious elements, they’re potentially safer for patients. The possible downside? Vaccines employing mRNA may need to be stored at incredibly cold temperatures — close to 100 degrees below zero, Fahrenheit — which has presented logistical challenges when it comes to distribution.

Pfizer’s vaccine was the first mRNA-based treatment ever approved, and Moderna’s was the second.

Do I need to get vaccinated if I’ve already had COVID-19?

The clinical trials from Pfizer and Moderna showed that both mRNA-based vaccines are safe for people who have already had COVID-19, so the current thinking is that people should get vaccinated, when possible, regardless of whether they’ve had it or not, although it should wait until they’ve recovered. (If someone were to get it after their first vaccine dose while waiting for the second, they should wait until after they’ve recovered to get the second one.)

That said, the most up-to-date evidence also suggests that reinfection is uncommon for about 90 days after the initial infection, so people might wait to get vaccinated until near the end of that period — if they want to.

Are these COVID-19 vaccines safe?

Vaccines have historically been remarkably safe and effective, and Dr. O’Leary believes both the Pfizer and Moderna vaccines — along with any other vaccines that might be approved — are no different.

That’s because, although the process has been accelerated, no corners are being cut. Both vaccines went through every single step of the vast, rigorous and complex process required to understand the safety and effectiveness of any new vaccine.

"This didn’t just happen in a year. This work is built on decades of remarkable progress in the development of vaccines,” says Dr. O’Leary. “I think we have many reasons to trust the process."

That goes not just for COVID-19 vaccines, but for the many other vaccines available. Dr. O’Leary notes that vaccination rates for kids have recently declined, potentially because families are avoiding healthcare providers’ offices due to the pandemic.

That would be a mistake, Dr. O’Leary says. Vaccines are the single best way to prevent disease: Kids need them to stay safe. That’s especially true this year, when COVID-19 has the potential to complicate other diseases in ways that are difficult to anticipate — including influenza. Dr. O’Leary urges families to make sure kids get their flu shot this year.

As for the COVID-19 vaccines, it may be a while before they’re available for anyone who wants one. And the pandemic isn’t over. COVID-19 cases and deaths are still on the rise — at worse levels, in fact, than they have been at any point during the pandemic. There’s still every reason to take precautions like social distancing and wearing masks.

But there’s a light at the end of the tunnel now, and that’s a lot better than the alternative.

“I’m optimistic,” Dr. O’Leary says.

Trustworthy sources on the COVID-19 vaccines


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