The top COVID-19 vaccine contenders, safety concerns, and health updates—all in one place.

By Melissa Mills
Updated December 02, 2020

With more than 64 million coronavirus infections—including 13.7 million cases and over 270,630 deaths in the U.S.—since the start of the pandemic, the race to develop a COVID-19 vaccine is on.

Progress is being made, and at a quicker pace than usual due to the White House's Operation Warp Speed, which aims to deliver 300 million doses of a safe vaccine to stop SARS-CoV-2, the virus that causes COVID-19, to the American public by January 2021. To date, two vaccine candidates—from Moderna and Pfizer—have shown success rates over 94 percent, meaning they could be the first to be approved for the public.

The Centers for Disease Control and Prevention (CDC) has told health officials to be prepared to distribute a coronavirus vaccine to health care workers, essential workers, and high-risk groups before 2021. Both Moderna and Pfizer have applied for emergency approval from the U.S. Food and Drug Administration (FDA) and first doses could be available by the end of December.

With coronavirus cases surging across the country and what experts say could be a bleak winter ahead, parents are wondering when, exactly, things will go back to "normal"—and what a vaccine could mean for their family.

Here, the latest on vaccine development, safety concerns, and everything you need to know about COVID-19 vaccines.

Vaccine Safety and Regulations

Despite the accelerated pace of Operation Warp Speed, the FDA has strict regulations that must be met before a vaccine can be distributed to the general public. To ensure the safety and effectiveness of a vaccine, it must go through three phases:

  • Phase 1: Early stage clinical trials on 20-100 healthy volunteers to test the safety profile, dose effects, and any adverse effects. If no serious side effects are discovered, the vaccine can move to phase 2.
  • Phase 2: Testing on hundreds of volunteers to determine any short-term side effects or dose effects on different categories of people. If deemed safe, the vaccine can move on to final trials.
  • Phase 3: Hundreds or thousands of volunteers are tested to evaluate the vaccine's effectiveness. This is where the FDA discovers if the vaccine prevents disease when compared to a placebo test and allows researchers to learn more about its safety and any common side effects.

Once this rigorous testing is complete and a vaccine is distributed to the public, phase 4—where the widespread effectiveness or long-term effects are tested on a greater population—will begin. To be considered effective, the FDA says that a vaccine should protect 50 percent of recipients.

"This unprecedented period has called for innovation, speed, and efficiency in vaccine production," says Mobola Kukoyi, M.D., MPH, an emergency physician at Carle Foundation Hospital in Urbana, Illinois who has seen both pediatric and adult COVID-19 cases in the emergency room. "Understandably, this comes with a concern for safety. However, given the different regulatory checkpoints in the phases outlined above, a product is only approved if it meets specific guidelines. My advice to all would be to follow the science."

The good news is that more than one COVID-19 vaccine candidate has already reached the phase 3 stage. According to Dr. Kukoyi, this "means we have something that has not shown any major side effects to date and has produced an acceptable immune response."

Vaccine Front-Runners

With more an 140 vaccines under development worldwide, a handful are showing promise. These are the ones to watch:

1. Moderna

Partnering with the National Institute of Allergy and Infectious Diseases (NAIAD), Moderna, a biotech company in Cambridge, Massachusetts, created the first vaccine to reach phase 3 testing.

"This is the main event, if you will, in drug development," Stephen Hoge, M.D., president of Moderna, told NBC News.

The first company in the U.S. to begin testing coronavirus vaccines in humans, Moderna—which was given $1 billion in support by the government—tested as many as 30,000 participants in phase 3, where half received the real vaccine and half received a placebo.

On November 30, Moderna announced that results show its vaccine is 94.1 percent effective—though data has shown it's 100 percent effective in preventing severe disease from the coronavirus—and has applied for emergency authorization from the FDA. Their hope? To begin vaccinating the public by December 21.

2. Pfizer

Pfizer, working with German company BioNTech and Chinese drugmaker Fosun Pharma, also began phase 3 clinical testing in September. This study included a more diverse group, including children as young as 16 years old, as well as people with HIV, Hepatitis C, and Hepatitis B.

The White House already announced a $1.95 billion deal to buy 100 million doses by December if testing goes well—and things are looking good so far. On November 20, Pfizer said that a final data analysis showed its vaccine candidate is 95 percent effective in preventing infection.

"Today is a great day for science and humanity," Albert Bourla, Pfizer's chairman and chief executive, said in a statement. "We are reaching this critical milestone in our vaccine development program at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen."

Pfizer has now applied for emergency authorization from the FDA, though the process is expected to take a few weeks.

3. Novavax

After a successful round of safe early clinical trials, Novavax, a Maryland-based company, has another vaccine to watch. Preliminary studies on monkeys and humans showed the production of virus antibodies, as well as killer T-cells, which can kill cells with the virus. Novavax plans to begin phase 3 testing in the U.S. in October.

On July 6, Novavax received $1.6 billion in support from the government to ramp up efforts and produce 100 million doses of a new vaccine by early 2021.

4. AstraZeneca

In collaboration with the United Kingdom's University of Oxford, British-Swedish pharmaceutical giant AstraZeneca has been awarded $1.2 billion to get 300 million doses of its vaccine contender ready for the U.S.

Early trial results have deemed the vaccine safe, but phase 3 clinical trials have been paused in the U.S. to allow for a review process after one participant developed an "unexplained illness." As of mid-October, a Brazilian volunteer in the vaccine study died but trials there were not paused, suggesting that the volunteer might not have received the vaccine.

AstraZeneca previously said it hopes to bring two billion doses of its vaccine to market early 2021. "We are rapidly progressing these clinical programs with the hope that results from our late-stage trials, which are currently planned to involve close to 50,000 volunteers collectively, will be available this fall," AstraZeneca executive vice president Menelas Pangalos told USA Today

5. Johnson & Johnson

With $500 million in backing from Operation Warp Speed, Johnson & Johnson's COVID-19 vaccine launched its phase 3 trials in September and is shooting to have data delivered early next year. As of mid-October, though, trials were paused after an "unexplained illness" in one of the volunteers.

In opposition to other fast-tracked coronavirus vaccines, Johnson & Johnson may take what they learned from their Ebola vaccine trials and include pregnant women in addition to pregnant animals in their late-stage testing.


Is the testing moving too fast?

"The speed which this vaccine will be brought to market is unprecedented," says Kevin Kathrotia, M.D., neonatologist and COO of Millennium Neonatology in Charlotte, North Carolina who has cared for babies whose mothers have tested positive for COVID-19. "This is a testament to the herculean effort of scientists and doctors at multiple companies, research facilities, and some of the world's greatest universities." 

And while things are moving faster than usual—it usually takes years to develop a vaccine, and a COVID-19 vaccine is set to be distributed within 24 hours of FDA approval—Dr. Kathrotia says that we should trust the clinical trial process and the fact that a drug brought to market is safe and works. "Having said that, I would wait to go completely back to normal until we see flattening and/or virtual elimination of the virus, which can lag full scale implementation of a vaccine." This means continuing to wear a mask, practice social distancing, washing your hands, and avoiding indoor gatherings or play dates. 

Who should get a COVID-19 vaccine?

We'll have to wait until phase 3 trials are complete to hear about health guidance and make informed decisions, but the federal government has confirmed that the vaccine will undergo a strategic rollout to the public.

"People at highest risk of exposure and severe illness should be prioritized for vaccination," says Dr. Kukoyi. "These include health care workers and other frontline providers; people with conditions that appear to increase COVID-19, severity such as hypertension, diabetes, asthma/lung disease, and obesity; those over age 60; those in long-term health facilities, and those in regions of high prevalence."

Dr. Kathrotia agrees: "Ideally, the vulnerable and high risk populations should be first in line for treatments."

While the vaccine will have a limited distribution initially, it will be free to the public after that.

Is it safe for children?

Vaccines that have been approved by the FDA should be safe, but some current COVID-19 vaccine clinical trials have excluded children. Pfizer is the first vaccine candidate to include children in its trials, starting with teens and moving to test kids as young as 12.

"There is no reason not to believe that [a vaccine] wouldn't be available simultaneously for adults and children," top infectious disease doctor, Anthony Fauci, told ABC News. However, some vaccine experts believe that children won't be given the COVID-19 vaccine upon initial release and that rigorous clinical trials on kids would need to happen first. In fact, children might not see a coronavirus vaccine until late 2021—and probably not in time for the new school year.

"It would be unfathomable giving children a vaccine that has not been adequately tested in children," Paul Offit, M.D., director of the Vaccine Education Center at the Children's Hospital of Philadelphia who sits on the Food and Drug Administration's vaccine advisory committee, also told ABC News. The American Academy of Pediatrics (AAP) has also come out urging officials to include children—as well as pregnant women and those with underlying comorbidities—in vaccine trials.

We'll know more about who should get vaccinated once a drug is ready for distribution. "We will need to rely on expert guidance after the first round of trials are completed to see how best to extrapolate the data for use in pediatrics, similar to our approach for other medical products," says Dr. Kukoyi.

That said, the CDC and AAP strongly recommend that all children continue to receive their routine vaccinations during the pandemic.

Is it safe for pregnant women?

Researchers are still studying how COVID-19 impacts pregnant women and fetuses, but pregnant women are not being included in current vaccine clinical trials. In fact, Reuters reports that drugmakers working on the top contenders are "requiring proof of a negative pregnancy test and a commitment to using birth control from women of childbearing age who enroll."

So, what does this mean exactly? Pregnant women may not be able to get a vaccine right away—or at least not until it's been proven safe through testing. This has sparked concern from health officials who have pointed out that pregnant women may be at a higher risk of complications from COVID-19.

How will I know if my family should get the COVID-19 vaccine?

It's still early and more research is needed, so health experts agree that families should follow the race for a vaccine candidate and let the data speak for itself once testing is complete. The FDA and government officials will likely share vaccination guidance once a drug has been approved.


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