Coronavirus and Cancer: What Oncologists Need to Know

Infectious diseases are the second-leading cause of mortality in patients with cancer, whose immune systems are often compromised, so it is essential for providers to keep abreast of the latest developments in the management of coronavirus disease 2019.

Christina Tan, MD, MPH

Infectious diseases are the second-leading cause of mortality in patients with cancer, whose immune systems are often compromised, so it is essential for providers to keep abreast of the latest developments in the management of coronavirus disease 2019 (COVID-19), according to Christina Tan, MD, MPH.1

"We’ve been finding that individuals with underlying medical conditions such as cancer might be immunocompromised and at a higher risk for complications associated with the virus that causes COVID-19,” said Tan, assistant commissioner of the New Jersey Department of Health and state epidemiologist.

“It is really important for clinicians to keep as updated as possible on the evolution of an emerging infection such as COVID,” she said. “With novel infections, we don’t know much at the beginning. Sometimes, when you’re looking for illnesses, you might need to modify what you’re looking for based on the newest information that’s available.” To date, fever, cough, and shortness of breath have been identified as symptoms associated with confirmed COVID-19 cases.2

According to a nationwide analysis of 1590 cases of laboratory-confirmed COVID-19 acute respiratory disease, published in February 2020, patients with cancer ”might have a higher risk” of contracting COVID-19. Patients with cancer had a higher risk of severe events (a composite endpoint defined as the percentage of patients being admitted to the intensive care unit requiring invasive ventilation, or death) compared with those without cancer (7 [39%] of 18 patients vs 124 [8%] of 1572 patients; P = 0003).3

Table. Risk Factors for Severe Adverse Events (Click to Enlarge)

Investigators concluded that patients with cancer and COVID-19 had poorer prognoses, adding that in the event of rapid deterioration, “more intensive attention should be paid to patients with cancer.” Alternatively, when patients with cancer are infected with SARS-CoV-2, the virus that causes COVID-19, “more intensive surveillance or treatment” should be considered.3

Cancer and Immunodeficiency

Certain cancer interventions such as chemotherapy and radiation therapy (RT) can reduce the number of infection-fighting white blood cells in bone marrow, temporarily weakening the immune system, a condition known as neutropenia. These treatments prevent the production of neutrophils, a type of white blood cell. Patients with neutropenia require closer monitoring for signs of secondary illness because they are more susceptible to viral and bacterial infections than individuals without neutropenia or cancer.4

Beyond chemotherapy and RT, targeted agents, steroids, and immunosuppressive therapies, such as mTOR inhibitors, also are associated with reduced immunity, according to Roy Chemaly, MD, MPH, FACP, FICSA, a professor in the Department of Infectious Diseases at The University of Texas MD Anderson Cancer Center in Houston, Texas.

Chemotherapy in particular is associated with off-target adverse events that affect the immune system, such as neutropenia. Although the immunosuppression seen with these interventions is not permanent, because neutrophil levels typically increase after patients complete their cancer treatment, research from Verma et al showed that, in breast cancer, chemotherapy can compromise the immune system’s ability to stave off or fight infection for up to 9 months after therapy.5

No Vaccine = No Defense

COVID-19 originated in Wuhan, China, in December 2019 and is thought to spread from person to person. There is no preventive vaccine or antiviral treatment for this novel virus. The Centers for Disease Control and Prevention (CDC) states that avoiding exposure to COVID-19 is the best way to prevent illness.2

However, avoiding the virus completely can be challenging because it may be hard to detect. Individuals can present with symptoms from 2 to 14 days after exposure to the virus that causes COVID-19.2 Those with the COVID-19 who have not been identified or entered quarantine may unknowingly expose others to the disease.

The virulence of infectious diseases such as COVID-19 can be attributed in part to a lack of immunity to the virus or disease. Vaccines deliver virus- or disease-specific antibodies to a person’s system, conferring immunity against the disease for which they were developed. Individuals who have immunity can be exposed to a virus or disease without contracting it.7

In contrast to vaccine-induced immunity, active immunity occurs when an individual’s immune system is exposed to an infecting agent and produces its own antibodies to combat the virus or disease. Once natural immunity has been established, the individual’s immune system will recognize the illness and immediately produce the necessary antibodies should the individual be exposed to it again in the future.6

The influenza (flu) is a virus, that, like COVID-19, poses risk to immunodeficient individuals, including patients with cancer. The key difference is that flu comes with a preventive option: the flu vaccine. This vaccine is developed and administered on an annual basis in response to the different strains of the virus that expected to circulate that year. Yearly vaccination is necessary to ensure that individuals receive the antibodies that will defend against these strains of flu.7

“We’re vulnerable to [the] flu because we don’t mount enough immunity, because there are different influenza strains every year. Natural immunity isn’t there,” said Roy Chemaly, MD, MPH, FACP, FIDSA, a professor in the Department of Infectious Diseases at The University of Texas MD Anderson Cancer Center in Houston, Texas.

Although the flu vaccine does not confer total immunity to the virus, the protection it does offer is valuable. Between 2017 and 2018, flu vaccinations prevented an estimated 6.2 million cases, 3.2 million flu-associated medical visits, 91,000 flu-related hospitalizations, and 5,700 deaths.7

The CDC recommends that all individuals ≥6 months of age get a flu vaccine each year, with rare exceptions including people with severe, life-threatening allergies to the vaccine or any ingredient that the vaccine might include.7,8 The immunization is strongly recommended for those who are in close contact with individuals at a high-risk for contracting the flu, such as clinicians, family members, and other caregivers.9

“The flu vaccine is the best way to protect patients [with cancer],” Chemaly said. “When family members and caregivers are immunized, it decreases the patient’s time at risk and helps break the chain of transmission.”

The flu vaccine is recommended across cancer types, but evidence has shown that it is less effective for patients with blood cancers compared with solid tumors. Investigators of a population-based study of 26,463 patients with cancer sought to evaluate the vaccine effectiveness (VE) of the flu vaccines administered in 2010 to 2011 and 2015 to 2016 in Ontario Canada. Data indicate that the VE was 8% in patients with hematologic malignancies (95% CI, -5%-19%) versus 25% (95% CI, 18%-31%) in patients with solid tumor malignancies (P = .015). Importantly, active chemotherapy usage did not “significantly” affect VE, authors said.10

Taking Precautions

Each season, different formulations of the flu vaccine are made available to the United States population and most of them protect against 4 different strains. There is also a recombinant vaccine, which delivers synthetic versions of these 4 strains, as well as a nasal spray that administers live but weakened versions of the 4 strains.7

For immunodeficient individuals and/or patients with cancer, particularly those with hematologic malignancies or those being treated with steroids or mTOR inhibitors, the CDC does not recommend the live formulation. This version of the vaccine can either cause flu or be less effective than the inactivated formulation.11

The flu vaccine can lessen the possibility of flu-related complications, which typically present with greater severity among patients with cancer versus the general population.9 For example, patients with cancer “may get pneumonia or a lower respiratory tract infection,” leading to oxygen deprivation and the need for mechanical ventilation, Chemaly said.

Patients with cancer who contract the flu have an increased risk for pneumococcal disease, a flu-associated complication that is caused by Streptococcus pneumoniae bacteria and can be deadly. Pneumococcal shots may be recommended for immunocompromised patients with cancer and can be given simultaneously with the flu shot.12

The flu and COVID-19 are similar in that they may both lead to serious complications for patients with cancer, but patients can take precautionary steps to protect themselves against the flu and COVID-19.

Whether individuals are specifically seeking to avoid “emerging infections or run-of-the-mill influenza,” several “common sense” health practices can be a useful defense, Tan said. “Wash your hands frequently, make sure that you cover your cough and your sneezes, stay home when you’re not well, and call your healthcare provider in the event that you have concerns about your health.


  1. Elfaituri MK, Morsy S, Tawfik GM, et al. Incidence of infection-related mortality in cancer patients: trend and survival analysis. J Clin Oncol. 2019;37(Suppl 15). doi: 10.1200/JCO.2019.37.15_suppl.e23095.
  2. Coronavirus Disease 2019 (COVID-19). Centers for Disease Control and Prevention website. Updated February 17, 2020. Accessed February 20, 2020.
  3. Liang W, Guan W, Chen R, et al. Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China. Lancet Oncol. 2020; doi: 10.1016/S1470-2045(20)30096-6.
  4. Megan Maisel. Cancer treatment side effect: neutropenia. MD Anderson website. Published March 21, 2017. Accessed February 19, 2020.
  5. Verma R, Foster RE, Horgan K, et al. Lymphocyte depletion and repopulation chemotherapy for primary breast cancer. Breast Cancer Res. 2016;18(1):10. doi: 10.1186/s13058-015-0669-x.
  6. Vaccines & Immunizations. Centers for Disease Control and Prevention website. Updated March 10, 2017. Accessed February 20, 2020.
  7. Key facts about seasonal flu vaccine. Centers for Disease Control and Prevention website. Updated December 2, 2019. Accessed February 24, 2020.
  8. Who should and who should NOT get a flu vaccine. Centers for Disease Control and Prevention website. Updated October 11, 2019. Accessed February 24, 2020.
  9. What cancer patients, survivors, and caregivers should know about the flu. Centers for Disease Control and Prevention website. Updated November 5, 2019. Accessed February 24, 2020.
  10. Blanchette PS, Chung H, Pritchard K, Earle CC, Campitelli MA, Buchan SA. Influenza vaccine effectiveness among patients with cancer: a population-based study using health administrative and laboratory testing data from Ontario, Canada. J Clin Oncol. 2019;37(30):2795-2804. doi: 10.1200/JCO.19.00354.
  11. Demarco C. Cancer patients and the flu: what you should know. The University of Texas MD Anderson Cancer Center website. Published January 19, 2018. Accessed February 24, 2020.
  12. Pneumococcal Vaccination. Centers for Disease Control and Prevention website. Updated November 21, 2019. Accessed February 24, 2020.

Also, patients with cancer “deteriorated more rapidly” than those without cancer (HR, 3.56; 95% CI, 1.65-7.69; P < .0001). Investigators added that patients who received chemotherapy or underwent surgery in the prior month were more likely to have clinically severe events than those who had not (75% versus 43%). A history of cancer conferred the highest risk for severe events (TABLE). Other risk factors included age, smoking history, and comorbidities.3