From cancer to medications to autoimmune diseases, there are many reasons a person may have a weakened immune system, but how might that affect their protection with the COVID vaccines?
The recent death of a suburban Chicago father with leukemia, who contracted COVID despite being fully-vaccinated, has raised some questions about vaccine efficacy in immunosuppressed individuals.
Current CDC guidelines indicate those with compromised immune systems should receive the vaccine, however, they should "be aware of the potential for reduced immune responses to the vaccine."
"I think there's still ongoing work about you know how well it works in people who are immunocompromised, but I think it's an important thing to still be vaccinated because you're still getting, you know, some level of protection from that vaccination," Dr. Candice Robinson, medical director for the Chicago Department of Public Health, said in a Facebook Live Tuesday.
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CDPH Commissioner Dr. Allison Arwady also acknowledged cases where some immunocompromised individuals have shown lower antibody levels post-vaccination, but said the vaccine could still provide some level of protection that would benefit those people.
"It's not that there's a problem with someone who is immunocompromised getting vaccinated. Usually, you know, like Dr. Robinson said, you 100% should get vaccinated, but there may be in people who, you know, are immunocompromised, and especially more severely immunocompromised... you may not get as high a level of protection," Arwady said. "So it's definitely been seen and for people who are seriously immunosuppressed it's a discussion you should have with your doctor."
The Leukemia & Lymphoma Society, citing data from a recent U.K. study, reports that "some blood cancer patients may not get optimal protection from the vaccines and may be more susceptible to COVID-19 infections after vaccination compared to the general public."
In that study from King’s College London, data showed that three weeks after one dose of the Pfizer vaccine, an antibody response was found in 39% of solid cancer patients and just 13% of people with blood cancer, compared to 95% in healthy individuals, the society reported.
The group urged blood cancer patients to continue wearing masks and taking preventative measures like social distancing and handwashing.
Similarly, a recent study from the University of Pittsburgh Medical Center found that "people with cancer that affects the blood, bone marrow or lymph nodes are at elevated risk of COVID-19 vaccine failure, particularly those with chronic lymphocytic leukemia."
The study tested blood from 67 patients with "hematologic malignancies" who had been vaccinated with either the Pfizer or Moderna COVID-19 two-dose vaccines three weeks earlier. The tests found that more than 46% of the participants had not produced antibodies against COVID-19 and only three in 13 patients with chronic lymphocytic leukemia had produced measurable antibodies, even though 70% of them weren’t undergoing any form of cancer therapy.
“As we see more national guidance allowing for unmasked gatherings among vaccinated people, clinicians should counsel their immunocompromised patients about the possibility that COVID-19 vaccines may not fully protect them against SARS-CoV-2,” the study's senior author Dr. Ghady Haidar, a transplant infectious diseases physician and assistant professor in the university's Department of Infectious Diseases, said in a statement. “Our results show that the odds of the vaccine producing an antibody response in people with hematologic malignancies are the equivalent of a coin flip.”
According to Haidar, however, a negative antibody test does not necessarily mean a patient isn't protected from the virus.
Many medications and treatments for certain cancers or other conditions can cause immune suppression or weaken an immune system.
The University of Chicago wrote in a blog post in February that there is little-to-no data surrounding the coronavirus vaccines' effectiveness in immunocompromised people because they weren't included in the vaccines' initial trials.
"Researchers don’t know whether these immunosuppressant treatments make the Pfizer and Moderna vaccines less effective – as some do in the case of flu vaccines – or if pausing or delaying treatment could make the vaccines work better. But it’s important that patients not change their treatment schedule without first speaking to their doctor," the university's post read.
With little data to offer, the Leukemia & Lymphoma Society is asking those living with blood cancers to register to become a "citizen scientist" and share their experiences with COVID-19 and the vaccines currently available.
The CDC said those with compromised immune systems should continue following the public health guidelines after vaccination.
Breakthrough cases - cases where fully vaccinated individuals test positive for coronavirus - have been reported across Chicago and the state.
Chicago's top doctor said Tuesday that the rate of infection post-vaccination is low, with 0.06% of fully vaccinated people contracting the virus.
"We've had more than 700,000 Chicagoans that are have a completed vaccine series - two weeks post their second dose, or two weeks post their first dose if they got J&J," Arwady said. "And at this point we've identified fewer than 500 breakthrough cases so that's, you know, 0.06% of those who had a completed series."
She noted that a majority of the cases were asymptomatic, but the city has seen 48 people hospitalized with COVID-19 post-vaccination and a total of five deaths.
"We're still looking at the cause of some of these, but I can tell you folks mostly were older, no surprise," Arwady said.
While the vaccine itself cannot give you the virus, it is also not 100% effective at preventing the virus entirely, though those who receive the vaccine are far less likely to be hospitalized or die from it, data shows.
According to the CDC, data from a multistate network of U.S. hospitals from January through March, showed the Pfizer-BioNTech or Moderna COVID-19 vaccines were 94% effective against COVID-19 hospitalization among fully vaccinated adults and 64% effective among partially vaccinated adults 65 years and older.
Chicago's data indicated the median age for fully-vaccinated people being hospitalized with COVID-19 was 72, with cases ranging from 24 years old to 97 years old. All five deaths were also reported in people over the age of 50.
Arwady noted that others getting vaccinated will also help to protect those with compromised immune systems.
"To take this one step farther, I think where someone who you know is seriously immunocompromised, they're gonna get vaccinated, but still, where there's a lot of COVID around that could be a setting where if, you know, they really want to make sure everybody who's in close touch with them is fully vaccinated, right?" she said. "It's just, it becomes extra important and probably taking some more care with masks, etc."