Identify cancer patients most at risk for breakthrough COVID

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Cancer patients who had undetectable antibody responses after COVID-19 vaccination face a three-fold increased risk of breakthrough SARS-CoV-2 infection and a more than six-fold increased risk of infection-related hospitalization than those with a positive antibody response, a new study reveals.

The results support the use of the SARS-CoV-2 spike protein antibody test to identify patients with the lowest level of antibody-derived protection and immunity against the virus, the researchers conclude.

“Antibody testing could allow these people to take additional preventive measures to reduce their risk of infection,” write lead author Lennard YW Lee, DPhil, from the University of Oxford, UK, and colleagues.

The study was published online on December 22 at JAMA Oncology.

People who are immunocompromisedincluding cancer patients, are much more likely to experience a breakthrough infection following the COVID-19 vaccination. However, identifying those with the lowest degree of protection and who are therefore most at risk of infection breakthrough remains less clear.

In the current study, Lee and colleagues aimed to understand whether the risk of SARS-CoV-2 infection breakthrough or hospitalization in cancer patients was related to their antibody responses after vaccination.

Using the UK National COVID Cancer Antibody Survey, researchers assessed 4,249 SARS-CoV-2 spike protein antibody test results from 3,555 cancer patients and 294,230 test results of 225,272 non-cancer control patients in the general population. Antibody tests were done after the second or third dose of vaccine.

In the cancer and control groups, individuals who received a third dose had significantly higher antibody titers than those who received only two doses (11,146.5 versus 8,765 U/mL for the cancer cohort and 23,667 against 12,126.0 U/mL for the cohort control group).

Lee and colleagues found that cancer patients were significantly more likely to have undetectable antispike antibody responses than control patients who did not have cancer (4.68% vs. 0.13%; P < .001).

Patients with leukemia or lymphoma had the lowest antibody titers – 19.3% had no detectable vaccine antibody response, compared to 4.2% of solid organ tumor patients and 0.1% of control patients. Patients who were receiving systemic cancer treatment and those with stage IV cancers were also more likely to have lower antibody titers.

After multivariate adjustments, cancer patients who had an undetectable antibody response had a three-fold increased risk of breakthrough SARS-CoV-2 infection (odds ratio [OR]3.05; P < 0.001) and a 6.5 times higher risk of SARS-CoV-2-related hospitalization (OR, 6.48; P < 0.001) than those with positive antibody responses.

Overall, in the cancer cohort, 259 patients had a breakthrough infection and 55 patients had a SARS-CoV-2-related hospitalization following their antibody test. Those who were hospitalized had significantly lower median antibody titers than those who were not (147.0 U/mL versus 10,961.0 U/mL).

The results suggest that the SARS-CoV-2 spike protein antibody test “can identify cancer patients who have the lowest level of antibody-derived protection and immunity against SARS-CoV- 2 and COVID-19,” the authors conclude. They note that to their knowledge, this is the first study to demonstrate such an association.

The authors acknowledge that they have not thoroughly assessed the delay between vaccination and antibody testing or checking for the effect of viral variants. The study took place at the end of the Delta wave and the beginning of the Omicron wave.

Nevertheless, Lee and his colleagues conclude that “wider access to antibody testing for people with cancer should be evaluated.” This “could help inform national guidance for clinicians advising patients and may provide a risk monitoring strategy that can be used to guide vaccination booster programs.”

The results can also help individuals make more informed choices about personal risks and precautions to take to reduce their risk of infection and transmission.

The authors note, however, that antibody testing is only “part of a larger strategy that includes collective efforts such as ventilation, filtration and two-way masking, which will make life safer for vulnerable and immunocompromised patients”.

The authors of a accompanying editorial offer additional strategies to meet the needs of the most vulnerable, including efforts to expand counseling and access to vaccines, improve access to antibody testing, and provide education on a range of topics, from how the virus is spreading how to reduce transmission in the home.

Overall, the editorial writers conclude that the study provides “compelling” evidence that cancer patients are more vulnerable to COVID-19 and suggest that “vaccines and antibody testing are key components of a comprehensive strategy to protect the most vulnerable oncology patients during the ongoing COVID-19″. 19 pandemic.”

The study was supported by the University of Oxford, University of Birmingham, University of Southampton, UK Health Safety Agency and Blood Cancer UK. A full list of author disclosures is available with the original article. The columnists revealed no relevant financial relationship.

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