Is SARS-CoV-2 screening test indicated for psoriasis patients candidate to biologic therapy?

Dear Editor,

Patients and physicians may be concerned about starting a biologic treatment during the COVID‐19 pandemic. Whether biologics enhance the risk of being infected with SARS‐CoV‐2 or whether the disease course is worsened remains to be ascertained. So far, no negative signal emerged for an increased risk of severe COVID‐19 associated with biologics when compared with the general population. ,

However, a universal screening for SARS‐CoV‐2 has been advocated for IBD patients who initiate a biologic treatment. , In this paper, we evaluate the pros and cons of a universal SARS‐CoV‐2 testing for psoriatic patients candidate to a biologic therapy. We consider the test options and then discuss their application in the above‐mentioned scenario.

Symptomatic patients

In a patient with respiratory symptoms, fever or anosmia/ageusia a SARS‐CoV‐2 testing with RT‐PCR test should be performed. In case of positivity, our personal suggestion is to keep a cautionary behaviour and to postpone the initiation of biological therapy after the acute phase has disappeared and testing for SARS‐CoV‐2 has been repeatedly negative.

Asymptomatic patients

The prevalence of positive molecular testing in asymptomatic patients might be relevant. In areas with a high prevalence of SARS‐CoV‐2 infection, it seems reasonable to test patients prior to a biologic therapy, even when asymptomatic.

However, current molecular and serological diagnostic tests for COVID‐19 have some limitations.

Nucleic acid amplification tests (NAAT) have only moderate sensitivity (likely between 63% and 78%), resulting in false‐negative results. Overall, this low sensitivity hampers the use of NAAT for a universal testing strategy in order to risk stratify patients. Moreover, it is important to consider the pretest probability from patient's contact history and his home town epidemiological data.

Serologic tests are commonly used to support clinical diagnosis or screening a patient for a certain treatment, by determining recent or prior infection. COVID‐19 serological tests are relatively inexpensive and accessible and can be useful in various ways.

However, there are several limitations that hamper the application of serologic test in screening of asymptomatic patients before a biologic therapy.

First, serologic tests are not useful for diagnosis of acute cases in the first week of illness, and as of now, there are lacking data on the magnitude and duration of antibody responses after asymptomatic or mild infections.

Secondly, some currently available serologic tests have a sub‐optimal specificity. A laboratory test with a specificity <100% may be of scarce utility in low‐prevalence settings.

If we hypothesize a COVID‐19 prevalence of 5%, the positive predictive value of a test with a 98% specificity dramatically declines to 71%, with almost one third of positive results being false‐positive.

Lastly, to date, the assumption that antibodies to SARS‐CoV‐2 confer protection from reinfection needs to be confirmed.

A recent consensus paper from the European Crohn's and Colitis Organization recommended that all patients with a IBD flare should be tested to exclude SARS‐CoV‐2 infection before starting a treatment. However, the International Organization for Inflammatory Bowel Diseases (IOIBD) and the British Society of Gastroenterology. suggest to test for SARS‐CoV‐2 patients with active IBD when needing inpatient endoscopic, radiologic or surgical procedures, but no specific recommendation for outpatients' management are proposed.

In fact, even though there is an agreement on recommending a SARS‐CoV‐2 testing when admitting a patient, the clinical meaningfulness of testing an outpatient candidate to a biologic therapy may be less obvious. Accordingly, NICE, National Psoriasis Foundation and EULAR recommendations do not mention the need of testing for asymptomatic patients before starting a biologic.

The need to screen patients for SARS‐CoV‐2 before starting a biologic treatment advocated by some gastroenterology experts and scientific societies , is mainly due to the fact that COVID‐19 may present with only fever and gastrointestinal symptoms, mimicking an IBD flare.

In conclusion, the optimal management of psoriatic patients in the era of this pandemic is challenging. There are several unresolved issues surrounding the use of the COVID‐19 diagnostic tests. NAAT remains the most useful test for diagnosis of acute COVID‐19 infections, but it has some drawbacks.

We believe that, at the moment and with the currently available diagnostic test, there is not enough evidence to support a universal molecular testing for SARS‐CoV‐2 in asymptomatic patients candidate to biologic therapy. We need to proceed with caution and provide intensive patient education, and decisions on a case by case basis can only be proposed.

Funding sources

None.

Conflict of interest

Stefano Piaserico has been a consultant and/or speaker for AbbVie, Almirall, Celgene, Janssen, Leo Pharma, Eli Lilly, Novartis, Sandoz and UCB. Paolo Gisondi has been a consultant and/or speaker for AbbVie, Almirall, Celgene, Janssen, Leo Pharma, Eli Lilly, Novartis, Pfizer, Sandoz and UCB. Simone Cazzaniga has nothing to declare. Girolomoni Giampiero has been principal investigator in clinical trials sponsored by and/or and has received personal fees from AbbVie, Abiogen, Almirall, AlphaSights, Amgen, Biogen, Bristol‐Myers Squibb, Celgene, Celltrion, Eli Lilly, Genzyme, Gerson Lehrman Group, Guidepoint Global, Leo Pharma, Menlo therapeutics, Novartis, OM Pharma, Pfizer, Regeneron, Samsung, Sandoz and UCB. Pier Giacomo Calzavara Pinton has been a consultant and/or speaker for AbbVie, Almirall, Celgene, Genzyme, Janssen, Leo Pharma, Eli Lilly, Novartis, Sanofi, UCB and Pierre Fabre. Luigi Naldi has been a consultant and/or speaker for AbbVie, Almirall, Celgene, Janssen, Eli Lilly and Novartis.