A Second Flu Shot Might Be More Effective in Some People With Lupus
- Effect of a second, booster, influenza vaccination on antibody responses in quiescent systemic lupus erythematosus: an open, prospective, controlled study.
Authors: Holvast A, van Assen S, de Haan A, Huckriede A, Benne CA, Westra J, Palache A, Wilschut J, Kallenberg CG, and Bijl M. (2009).
Rheumatology 48: 1294-1299
What is the topic?
One of the ways that the immune system fights off the flu is by making antibodies (immune proteins) that can recognize the flu virus and attack it. The immune system can also make little chemicals called "cytokines" that signal to the white blood cells to make more of these antibodies when there is a virus in the bloodstream. The flu shot is made with dead virus that can help a patient make protecting antibodies but won’t cause the full flu infection to start up. In this way, individuals can be protected in advance before they are exposed to the flu that is "going around" in their community. Some lupus patients make fewer antibodies to the flu shot than most people, and there is some concern that medications for lupus can reduce the response to the flu shot since they can suppress the immune system in other ways. If there was a way to increase these responses, then the flu shot might be more effective for people with lupus.
What did the researchers hope to learn?
The researchers wanted to find out whether a second, "booster" flu shot could increase antibody responses in lupus patients.
Who was studied?
The study included 52 lupus patients and 28 healthy people of about the same age and the same percentage of women and men. The lupus patients were not flaring at the time and thus their lupus symptoms were relatively quiet. Most of them were taking some immune-suppressing treatments. No one in the study had cancer or was taking more than 30 mg/day of prednisone. Most people in both groups had gotten a flu shot the previous year.
How was the study conducted?
The flu shot that was used is called a "subunit" vaccine, which means that it has enough pieces of the flu virus to cause antibodies to be made, but may be missing other parts of the flu virus. All of the people participating in this study got at least one flu shot. Four weeks later, the lupus patients, but not the other people, got a second booster flu shot. Antibodies against the flu virus were measured before each shot, and again four weeks after the time of the second shot.
What did the researchers find?
The researchers found that a second flu shot did not increase the overall amounts of flu antibodies if you looked at the whole group of lupus patients compared to healthy people. However, a sub-group of the lupus patients who had not gotten the flu shot in the previous year did show an increased antibody response with the booster vaccination.
Neither the first nor second flu vaccination increased lupus disease activity, but both caused more frequent minor side effects in lupus patients than in healthy people. The kinds of side effects seen in lupus patients were similar after the first and second flu shots.
What were the limitations of the study?
This was a small study. Also, it did not include a group of lupus patients given only one flu shot, which could have been useful to compare to those who got two shots.
What do the results mean for you?
Increased antibody responses to a second, booster flu shot were seen only in lupus patients who had not received a flu shot in the previous year. Therefore, the additional benefit for lupus patients who get a second flu vaccination may be just for those not vaccinated against influenza in the previous year.