News & Events

A COVID-19 Vaccine: How will we know it's safe?

By Darcie Fisher, Tufts Medical Center Correspondent 

You’ve not doubt heard that several COVID-19 vaccines are currently in clinical trials – but many are wondering how safe these “fast-tracked” vaccines will be and when they will be available.  We sat down to talk with two experts from Tufts Medical Center and asked them to weigh in on many common questions people have about a vaccine. Helen Boucher, MD is the Chief of Geographic Medicine and Infectious Diseases and Shira Doron, MD is the Hospital Epidemiologist.

What is the status of the trials?  

There are multiple vaccines currently in clinical trials with tens of thousands of participants taking part across the country. These studies are “double blind,” meaning that some participants are getting the actual vaccine and others will get a placebo. 

“It is expected that more than one vaccine will be approved by the FDA,” says Dr. Shira Doron. “While there is no guarantee that the first one will actually be the most effective one, the FDA has protocols in place to ensure that all COVID-19 vaccines are both safe and effective.”

How safe are “fast-tracked” vaccines?  

“A key message is that no vaccine will be recommended that isn’t acceptably safe,” says Dr. Helen Boucher.  “Whether and when we know which one is the most safe and effective for which group of patients could be farther down the road.”  

Dr. Boucher points out there is a general misconception that “fast tracking” means cutting corners in terms of safety, but she says that is not the case. “What ‘fast tracking’ means in terms of speeding up approval has little to do with the actual trials, and more to do with producing the vaccine,” explains Dr. Boucher.  “Pharmaceutical companies involved in the trials are already manufacturing these potential vaccines ahead of knowing whether its vaccine will be approved.  This is done so that if and when a vaccine proves to be both safe AND effective, there are already manufactured doses ready to be administered to the public. Traditionally, vaccines do not go into production until after FDA approval.” 

Who oversees the integrity of the actual trials?

“There are monitoring committees tasked with carefully overseeing each of these vaccine trials,” says Dr. Boucher. “These committees are made up of trusted and experienced physicians, scientists, statisticians, and ethicists who are completely independent of the FDA as well as the companies and investigators who sponsor and conduct the trials.”  Known as DSMB’s (data and safety monitoring boards) Dr. Boucher says they have the obligation to ensure the safety of those participating in the clinical trial.  DSMB’s also have the power to recommend a study be paused or stopped entirely if a vaccine appears to be unsafe, she noted.  “These committees are given updates on data at regular intervals during the trial so they can determine if sufficient evidence has been collected which proves a vaccine is effective,” explains Dr. Boucher. “Vaccine study protocols also ensure a trial does not go on longer than needed if a crucial health benefit is shown.”

When do you anticipate a COVID-19 vaccine will become available?  And who will be able to get it first? 

Both physicians say the earliest they believe a vaccine will be available is spring or summer of 2021. “In terms of who will get the COVID-19 vaccine first, there is a set protocol created this year from the National Academies of Sciences, Engineering and Medicine,” says Dr. Doron. “The protocols are broken into four phases.” Here are the phases:

Phase 1A: 

  • High-risk health care workers
  • First responders

Phase 1B: 

  • People of all ages with underlying conditions that put them at significantly higher risk
  • Older adults living in congregate or overcrowded settings

Phase 2:

  • K-12 teachers, school staff and child-care workers
  • Critical workers in high risk settings
  • People of all ages with underlying conditions that put them at moderately higher risk
  • People in homeless shelters or group homes, as well as staff in these settings
  • People in prisons, jails, detention centers and similar facilities and staff in these settings
  • All older adults not included in Phase 1

Phase 3: 

  • Young adults
  • Children
  •  Workers in industry important to the functioning of society and at increased risk not included in Phase 1 or 2

Phase 4:

  • Everyone living in the United States who did not have access to the vaccine in previous phases

What does emergency release of a COVID-19 vaccine mean, and would that vaccine be safe?

“Releasing a vaccine in this manner is known as an EUA, or Emergency Use Authorization,” explains Dr. Boucher.  “An EUA authorization is an option the FDA can exercise during a pandemic to make medicines, diagnostic tests or vaccines available. As the name suggests, this is done in case of an emergency, but we would not recommend an EUA-approved vaccine unless we believe it to be safe. The companies involved in the vaccine trials have all signed a pledge stating they will not request approval for a drug that isn’t safe. Patients who take part in these trials must be followed for two months after they have been given the vaccine. The two-month time period is to make sure patients do not suffer any adverse side effects as well as evaluating the effectiveness in protecting them from developing COVID-19.

Do you anticipate a mandate for the COVID-19 vaccines?

“We’ve never seen a national mandate before, but we’ve never been in a situation like this before,” says Dr. Doron. “Still, I do not anticipate a mandate. The real conundrum is when FDA approval or authorization comes, will that be enough for public acceptance and to end hesitancy? We need a significant percentage of the population to step forward and take the vaccine to speed up the end of the pandemic.”

Are there any instances in this country were vaccines were released before they were proven safe for the public?

In 1976 more than 40 million people received an influenza vaccine which many felt was rushed to market, noted Dr. Boucher. That particular flu shot was linked to at least 500 cases of Guillain-Barre’ syndrome. “As a result of that unfortunate incident we have stricter protocols in place today to minimize risk associated with taking new vaccines or medications,” says Dr. Boucher. “Many lessons were learned which are being applied to the COVID-19 vaccine trials and to countless trials which have taken place over the last four decades.”

Is there an end in sight to wearing masks and social distancing?

“This vaccine isn’t a magic bullet,” says Dr. Doron. “There will not be enough at first to vaccinate all of the United States.  Plus, the government will have to go through the logistics of applying the set framework of who gets it when, and that takes time. You’re not going to see an immediate disappearance of COVID-19 when the vaccine is released.”  

Dr. Boucher says there is a “hard message” she and her colleagues across the country must get across to the public. “We’re in a better place than we were in March. Testing is better. General treatment of patients is better, and there are more medicines coming to assist us.  It’s staggering, however, when you realize 90% of the population still hasn’t been exposed to COVID-19, so to get to a place where we can say masks are no longer required and physical distancing can be relaxed will take a significant amount of time.”  

Still her message is one of hope. “Things are going to get better.  This will end. I am hopeful. Realistically speaking, I believe we are looking at another solid year before things will get back to normal.”

Both Dr. Doron and Dr. Boucher emphasize the need for good hand washing, wearing a mask, physical distancing, avoiding crowds and not going to work or school when you feel sick.


Posted October 2020 

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