New study backs flu vaccine for RA

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New study backs flu vaccine for RA

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Aug 18, 2005

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Gandey

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(Source: Centers for Disease Control and Prevention)

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Tel Aviv, Israel - Concerns about the safety of vaccinating patients

with rheumatoid arthritis (RA) for influenza are unfounded, say Israeli

researchers. In an online article in ls of the Rheumatic Diseases,

researchers show that vaccination does not modify the clinical picture

of RA, and long-term immunosuppressive therapy at conventional doses

does not adversely affect humoral response [1]. Led by Dr Irina Fomin

(Tel Aviv University, Israel), the researchers explain, " The humoral

response was not affected by different clinical and demographic

characteristics of RA or by the use of commonly administered

disease-modifying antirheumatic drugs [DMARDs], including methotrexate

and infliximab. "

But not everyone agrees. Previous studies have shown that immune

response can vary depending on prior treatment with antirheumatic

drugs. In October 2004, a team presenting in San , TX at the

American College of Rheumatology annual scientific meeting showed that

pneumococcal vaccinations are beneficial to patients with RA. Speaking

to the press, one of the study's authors, Dr Pierre Geborek (Lund

University Hospital, Sweden) said, " RA patients treated with TNF

blockers can be safely vaccinated against pneumococcal infections under

the same premises as patients with other diseases. " But unlike the

findings of the present study, Geborek had cautioned at the time that

methotrexate-treated patients should preferably be vaccinated before

initiation of this treatment.

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This is an important issue to report, since 'rumors' of vaccination as

a trigger of diverse rheumatoid inflammation and possibly also disease

onset are very difficult to extinguish.

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Geborek told rheumawire that he has important concerns about the

findings of this new study. He questions Fomin and her team's position

that antirheumatic drugs do not influence immune response. " This is

actually not possible to conclude from this study, since it does not

include a formal RA population without antirheumatic treatment. The

authors make a try by grouping patients into prevalence of different

treatments, but it is clear that several of the actual treatments must

be given in combination with other DMARDs. " Geborek argues that the

same patient is a member of several groups and it is therefore

impossible to disentangle the contribution of a single treatment. " For

instance, " he explains, " infliximab is almost universally given

together with methotrexate, and it could well be that one drug actually

enhances immune response while the other diminishes this response.

While allowing for this type of analysis, the authors have refrained

from any possible valid conclusions of a single drug's contribution to

the influenza vaccine immune response. "

Geborek adds, " There are some other possible statistical pitfalls the

authors may have fallen into, such as using the T-test without stating

the distribution of the material and not enclosing age into the

multiple regression model, but I doubt that this would have changed the

results significantly. " Geborek says the researchers were right to

outline in detail that vaccination does not worsen RA disease activity.

" This is an important issue to report, since 'rumors' of vaccination as

a trigger of diverse rheumatoid inflammation and possibly also disease

onset are very difficult to extinguish, " he said.

" Overall, the conclusion that RA patients on diverse DMARD treatment

tolerate influenza vaccination and elicit similar immune response as

controls is probably valid, " Geborek said. " However, any influence of

DMARD treatment on the immune response is not possible to evaluate in

this study. "

Flu shot " strongly indicated " for RA

In the present analysis, Fomin and colleagues looked at 82 patients who

fulfilled the American College of Rheumatology criteria for RA and 30

healthy controls. All participants were administered an influenza

split-virion inactivated vaccine. The researchers assessed disease

activity by the number of tender and swollen joints, morning stiffness,

pain, health assessment questionnaire, erythrocyte sedimentation rate,

and C-reactive protein on the day of vaccination and six weeks later.

They tested hemagglutination-inhibiting (HI) antibodies using a

standard World Health Organization procedure. The investigators defined

response as a more-than-fourfold rise in HI antibodies six weeks after

vaccination or seroconversion in patients with a nonprotective baseline

level of antibodies (<1/40). They calculated geometric mean titers to

assess the immunity of the whole group.

Six weeks after vaccination, the investigators observed a significant

increase in geometric mean titers for each antigen in both groups.

Fomin and colleagues report that the percentage of responders was not

affected by prednisone or any DMARD, including methotrexate,

infliximab, and etanercept.

" Reduced compliance to administer vaccination against influenza is

related to concerns about its safety and doubts regarding its

immunogenicity, " comment the researchers. Much like previous studies,

which showed that patients with RA and systemic lupus erythematosus did

not experience significant clinical flares following vaccination, the

group writes, " Our present results reconfirm the safety of influenza

vaccination in RA. "

The researchers point to the limitation of the small size of their

study, but they say they are confident that vaccination against

influenza is " strongly indicated " in RA.

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Source

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http://www.jointandbone.org/viewArticle.do?primaryKey=544743

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