Influenza vaccine effective in cancer patients
medwireNews: The influenza vaccine has “modest” effectiveness in patients with cancer, say researchers who believe their findings support public health recommendations for vaccination in this population.
Vaccine effectiveness (VE) among cancer patients was lower than that for the general population, and appeared to be significantly better for patients with solid tumors than hematologic malignancies, they add.
The team therefore highlights “a need to develop improved influenza vaccines for patients with cancer, especially among older patients and those with hematologic malignancies.”
Phillip Blanchette (London Health Sciences Centre, Ontario, Canada) and team used a test-negative study design – a variant of a case–control design – to calculate VE from data on 26,463 cancer patients, taken from a collection of laboratories linked to population-based health administrative databases.
The patients, each with a previous diagnosis of cancer, underwent diagnostic testing for influenza during the 2010–2011 to 2015–2016 influenza seasons. Of these, 16% tested positive for influenza and 45% had received a seasonal influenza vaccine (at least 14 days prior to specimen collection).
Vaccination against laboratory-confirmed influenza was effective in 21% of cases, after adjusting for cancer-related factors and medical comorbidities. Additionally, it was effective against laboratory-confirmed influenza hospitalization in 20% of cases.
Sixty-nine percent of the study participants had a solid tumor malignancy (most commonly breast, lung, or prostate malignancies), while the remaining 31% of patients had a hematologic malignancy, most commonly leukemia or non-Hodgkin lymphoma.
The researchers note in the Journal of Clinical Oncology that the influenza vaccine was 25% effective in patients with solid tumor malignancies, which was significantly higher than the 8% effectiveness observed in those with a hematologic cancer.
They highlight, however, that their research “could not determine the extent to which this difference was due to disease versus treatment-associated immunosuppression.”
No significant difference was observed in VE between patients who were undergoing active chemotherapy and those who were not, especially among patients with solid tumors.
But the researchers suggest that “the effect of active chemotherapy usage may be more important among patients with hematologic cancers who often experience profound myelosuppression due to treatment with high-dose chemotherapy.”
Blanchette and co-authors conclude: “Overall, our results support current clinical practice guidelines recommending influenza vaccination for patients with cancer and survivors,” adding that “[t]his recommendation acknowledges the safety of vaccination and the potential severity of influenza infections among strongly immunocompromised patients with hematologic cancers.”
By Hannah Kitt
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