Disease condition and its impact on patients: Seasonal influenza causes disease all year, globally. Illness ranges in severity: most people recover within 1 week without requiring medical attention, but influenza can lead to hospitalization and death. Does this test meet a medical need? The RDT provides a result within 10–15 min, therefore allowing physicians and nurses to diagnose influenza and decide on treatment at a single patient visit. How the test is used: Immunoassays for influenza are typically used at or close to points of care as a single test in patients with suspected influenza.

Prevalence: Worldwide, seasonal influenza is estimated to result in 3–5 million cases of severe illness and about 290 000–650 000 deaths from respiratory conditions. The US Centers for Disease Control and Prevention estimated that influenza has caused 9.3–49.0 million cases of illness, 140 000–960 000 hospitalizations and 12 000–79 000 deaths annually in the USA since 2010. WHO states that the estimated national influenza burden determines influenza prevention and control programmes; however, reliable data are not available for LMICs. Socioeconomic impact: The WHO project on the burden of influenza, in partnership with the Pandemic Influenza Preparedness framework, is improving understanding of the burden of influenza (1).

WHO recommendations on the use of rapid testing for influenza diagnosis (2, 3). The latest guideline is from 2010 and should be updated. Laboratory confirmation of influenza virus from throat, nasal and nasopharyngeal secretions or tracheal aspirates or washings is commonly done by direct antigen detection, virus isolation or detection of influenza-specific RNA by RT-PCR.

WHO Recommendations on the use of rapid testing for influenza diagnosis (2) indicate that a rapid diagnostic test performed within 48 h of the onset of symptoms can have important implications for case management, including the use of antiviral agents. Other benefits may include the isolation and cohorting of confirmed cases to prevent nosocomial outbreaks and a reduction in inappropriate use of antibiotics. Use of rapid tests that provide timely evidence of influenza virus infection should be considered; however, test performance depends on the prevalence of influenza in the community. A low prevalence outside the normal influenza season can lead to an increase in false-positive results.

In 2010, computer simulations were used to evaluate the economic value of seven strategies for testing and managing seasonal and pandemic influenza: clinical judgement alone, PCR, an RDT at points of care, a combination of a point-of-care test and clinical judgement, clinical judgement with confirmation by PCR, treating everyone with antivirals and treating no one with antivirals (4). For healthy adults < 65 years presenting with influenza-like illness in a seasonal influenza scenario, strategies were cost–effective only from a societal perspective. Clinical judgement, followed by PCR and point-of-care testing, was found to be cost–effective in situations of a high influenza probability. Doubling the hospitalization risk and mortality (representing either individuals at higher risk or more virulent strains) made clinical judgement to decide on prescription of antiviral agents cost–effective, as did PCR testing, point-of-care testing and point-of-care testing in conjunction with clinical judgement. For healthy adults ≥ 65 years, PCR was the most cost–effective option, the closest competitor being clinical judgement, with an accuracy ≥ 50%. Point-of-care testing plus clinical judgement were cost–effective for higher probabilities of influenza. Treating all patients with influenza-like illness with antiviral agents was cost–effective only for older adults. This study showed the importance of accuracy, with PCR or highly sensitive clinical judgement.

Consent is required to obtain a sample. RDTs for influenza are readily accessible for use in outpatient settings. The typical price in the US of US$ 9–15 per test may limit access in LMICs. However, pricing of the same products in LMIC’s may not be the same as in the US and was not available at the time of submission.