Cancer patient holding covid vaccine information card

COVID vaccine and cancer: What patients need to know


Published: Mar 29, 2021 at 12:57 PM EDT

The development and availability of COVID-19 vaccines has stirred up many questions, as well as some confusion. The influx of COVID vaccine information (and misinformation) can be even more daunting for cancer patients and survivors.

To help cancer patients better understand the vaccines, Provision CARES Proton Therapy hosted a special chat session with board-certified radiation oncologist Dr. James Gray, who gave a great presentation on “COVID-19 Vaccine and Cancer: Facts vs. Fiction.”

In this article, we’ll highlight some of Dr. Gray’s main points about the COVID-19 vaccine and how it relates to anyone who has been affected by cancer. You can also view the entire presentation in the video below.

James Gray, MD, FACRO, Medical Director at Provision CARES Proton Therapy Nashville


Even though this is the top of the article, we’ll start with the bottom line, because it is Dr. Gray’s most important point: The majority of cancer patients and survivors should get the COVID vaccine.

Having a history of cancer means you have a slightly higher risk of significant illness from COVID-19. While we don’t know exactly why this is, it’s most likely due to the fact your body is already battling (or has battled) a chronic illness.

There are only a few small groups of cancer patients who may wish to delay getting the COVID vaccine:

  • Patients currently on chemotherapy who have diminished white blood cell counts
  • Patients with advanced hematologic cancers (e.g. leukemia, lymphomas) who may undergo a stem cell transplant
  • Patients having major surgery soon

Because of the nature of how the vaccines work, they may not be effective in someone with a suppressed immune system. The vaccine likely won’t harm anyone in these groups, it just may not work.

People who fall into these categories are advised to wait until their immune system recovers, then get vaccinated. But anyone else, including patients undergoing proton therapy, should get the vaccine as soon as possible.

“You have a responsibility to the society that you live in. You don’t want to transmit the virus to someone else,” says. Dr. Gray. “The best way to do that is to not let it set up shop in your body. And that’s called vaccination.”


Dr. Gray began his presentation by discussing what COVID-19 is exactly and why it’s such a problem. COVID-19 is a disease caused by a virus called SARS-CoV-2, a type of coronavirus. You may have heard it initially referred to as a “novel” coronavirus. That means it is a coronavirus that was not previously seen in humans, so our bodies are not able to counteract it like they’re supposed to.

There’s no question the pandemic is a problem. But cancer is also a problem. They coexist and neither of them cares about the other.

Early on in the pandemic, physicians tried to delay cancer care and diagnoses as much as possible. For instance, many prostate cancer patients could afford to try and “wait it out” and didn’t necessarily need to be treated right away.

However, many cancer cases can’t wait. As the pandemic lagged on, it was clear patients needed to continue moving forward with screenings, treatments, follow-ups, etc. In fact, even when the pandemic began and many businesses temporarily closed their doors, Provision never stopped treating cancer patients, because as Dr. Gray put it, “Cancer doesn’t care about the pandemic.”


The ultimate goal in battling the COVID-19 pandemic is to squash the virus enough so society can “get back to normal.” In order to be in a place where large events like football games and live concerts are safe to attend, we have to get back to where it doesn’t matter if you’re near someone who is infected with the virus.

To get there, the general consensus among the scientific community is that about 75-80% of the U.S. population needs to be immune. So how do reach that number?

The argument that we should let the virus take its course and the population will develop herd immunity is unrealistic, considering how many deaths would have to occur before we reached 80% immunity.

We need a faster, safer way – a way to obtain immunity without being exposed to the virus. We need to teach our immune systems to react against the SAR-CoV-2 virus as soon as it enters our system, so our body can suppress it before it even becomes an issue.

That’s where vaccines come in.


At the time of this blog being published in March 2021, there were three vaccines available in the United States. None of these had permanent FDA approval at the time, but they were all approved for emergency use.

In the video below, Dr. Gray does a great job of explaining how the vaccines actually work and why they’re so effective.

He discusses the technology behind the first two vaccines that were made available in the U.S. – Pfizer and Moderna. These are known as Messenger RNA (mRNA) vaccines. In simple terms, a piece of RNA is wrapped inside a container known as a liposome, then injected into your muscle. It then instructs your cells how to create a “spike protein.”

Computer generated image of spike proteins covid vaccine recognizesIf you’ve seen a microscopic image of the SARS-CoV-2 virus, you’ll recognize its “spiky” look. The spike proteins created by the vaccine look similar, but they are harmless. Since they are foreign to your body, your immune system develops a reactivity against them.

Once you are fully vaccinated, your body will be trained to fend off these “spiky” looking things. So, if the actual virus were to enter your body, your immune system knows exactly what to do. It charges up and goes to work, making the likelihood of developing COVID-19 very low.

This “charged up” immune system is most likely why some people feel unwell after getting the vaccine. The body is reacting much like it does any time the immune system is activated – fever, aches and pains, fatigue. It’s important to remember that the vaccine is not putting anything harmful into your body.


Dr. Gray also addressed many of the most common concerns he’s heard about getting the vaccine.

“A lot of people distrust the vaccine,” he says. “Some of that distrust is built upon fears that aren’t genuine.”

For instance, some people remain worried that vaccines, in general, can cause autism. While the research that first stoked that fear was largely rebuked by the scientific community and the authors eventually retracted it, the idea took root and has never been fully put to rest. The fact is there is no statistical link whatsoever between vaccines and autism.

Other concerns heard in the medical community include a fear of the vaccine changing someone’s DNA, or that the vaccine was made from the embryonic tissue of an aborted fetus. Dr. Gray says these fears are also unfounded.

He also says some people are afraid to get the vaccine because they’re afraid they’ll actually get the virus from it. However, that fear is based on old vaccine technology, in which deactivated particles of the actual virus were injected into your body.

“We can’t get infected with the virus by having the vaccine, because we’re not getting the virus,” says Dr. Gray, noting the newer mRNA technology that doesn’t use the entire virus.

The most logical disagreement Dr. Gray has heard is that the testing period for the COVID-19 vaccines was too short.

While he agrees the testing period was rapid, it’s also important to point out that clinical testing for the vaccines was monitored by the FDA and went through approved protocols. In addition, the science behind the mRNA vaccine technology is very strong and well developed.

We don’t have long-term data, of course, because the virus is so new. However, infectious disease experts around the globe generally agree that the risk of getting the virus and getting sick is clearly higher than any long-term vaccine risk.

“If you ask any expert who understands this really well, an immunologist for example,” says Dr. Gray, “The long-term risk is not zero, but it’s almost guaranteed to be lower than getting the virus.”