The high-dose influenza vaccine is almost three times more likely to be protective than the standard dose vaccine in people with rheumatoid arthritis, according to a Canadian study.
Around 280 patients with seropositive RA were given either the high dose trivalent influenza vaccine or the standard dose trivalent influenza vaccine in a randomised, double-blind trial.
Patients who received the high dose vaccine were 2.8 times more likely to form protective antibodies against H3N2 than those on the standard dose.
The seroconversion rate for H1N1 and B/Brisbane were, respectively, 2.3 and two times higher in people on the high dose vaccine compared to those on the standard dose.
Adverse events were similar in both treatment groups, with around 30% of patients in each arm reporting side effects.
The study, unveiled at the American College of Rheumatology annual meeting in Chicago in October, is the first to document the success of high dose flu vaccine in patients with RA.
“Because of these conclusions we believe that these results will likely change clinical practice,” Associate Professor Ines Colmegna, a rheumatologist at McGill University in Canada who was the study’s presenting author, said.
Patients with RA are more likely to contract the flu than healthy people of the same age, and are at greater risk of major complications, such as pneumonia, stroke, MI or neurological complications.
“These [greater risks] derive from inherent immune dysfunction associated with RA, co-morbidities, the age of our patients and immunosuppressive therapy,” Professor Colmegna said.
For this reason, the annual flu shot is funded in Australia for patients with immunocompromising conditions, such as RA. However, like older people, RA patients under the age of 65 have a suboptimal immune response to the standard dose influenza vaccine.
Could the high dose flu shot be the answer? Perhaps, but prescribing habits would really depend on the cost of the vaccine to the patient, Dr Helen Keen, a rheumatologist based in Perth, said.
Fluzone High-Dose was added to the NIP in February for people aged 65 and over, but patients under this cut-off age were not eligible for a free high-dose flu shot.
“I do think that the results of this study should encourage rheumatologists to offer patients with RA the high-dose vaccine, especially in older patients for whom it is government-funded,” Dr Mona Marabani, a Sydney-based rheumatologist and past president of the Australian Rheumatology Association, said.
“One caveat is that we don’t have any information regarding actual clinical cases of influenza in these patients post-vaccination.”
The Canadian study showed that RA patients under 65 could also benefit from the high dose influenza vaccine. The average age of people in the study was around 61 years. A spokesperson for the Federal Department of Health said the use of Fluzone High Dose among individuals aged less than 65 years had not been approved by the TGA or recommended by the PBAC.
Christian Felter, the head of medical at Sanofi Pasteur (which supplies Fluzone High-Dose in Australia) said the company understood the need for improved flu vaccines for RA patients, but that the current indication of high-dose vaccine was only for those aged 65 years or above.