Virus specificity

Specificity was evaluated using 10 pre-pandemic sera, i. Furthermore, 9 potential cross-reactive sera were included, i. Sensitivity and specificity were calculated for each test. Sensitivity and specificity were calculated by means of Excel version All patients consulting at the emergency department of our hospital from the 1 st of March till the 14 th of May, with symptoms suggestive of COVID disease that required hospital admission and for which laboratory diagnosis was performed in our institution were retrospectively included in a database.

If the initial nasopharyngeal swab was found to be negative, a second nasopharyngeal and additional anal swab were analyzed. If still negative, a bronchoalveolar lavage BAL was performed. In our institution a total of patients were hospitalized with an in-house laboratory confirmed COVID diagnosis. Another 4 patients were diagnosed with a second nasopharyngeal and 1 patient with an anal swab. Next, 5 patients were found to be positive on BAL samples. Three patients remained negative on repetitive swabs.

These patients were not eligible for a BAL sampling procedure or did not present with respiratory symptoms and as such serological testing was performed.

As expected, we found that sensitivity was higher if the test was performed starting from day 8 after symptom onset, as compared to earlier time points. Recently, the first studies evaluating several commercial serology assays have been published. Geurts van Kessel et al [ 17 ]. The group of Haselmann et al [ 16 ]. Serrano et al [ 18 ]. The lateral flow immunoassays showed variable performances. Pieri et al. Instead, IgG, as expected, showed stable level after 10 days from symptoms onset [ 21 ].

These findings are in accordance with our study results. Serological tests could be useful in some clinical settings.

The availability of these serological tests might avoid the need for more invasive sampling methods like BAL in the pursuit of diagnostic confirmation of COVID, especially.

Furthermore, serology can aid in infection prevention management. Nuccetelli et al. Next the development of antigen detection assays are underway, which have the potential to rapidly detect active SARS-CoV-2 infection. As the pandemic evolves, more and more insights will be gained in the value of serology as well as antigen detection [ 23 ]. The main limitation of the current study is the limited number of samples included.

Nevertheless, this study has evaluated the performance of 14 different serological assays and therefore could provide useful information in this stage of the pandemic. In conclusion, our findings show that sensitivity was variable but increased in a later stage of infection at least 8 days after symptom onset.

Our data suggest that virus-specific antibody detection for SARS-CoV-2 can complement molecular testing for diagnosis of COVID, especially for patients presenting in the 2 nd week or later after symptom onset. Larger datasets should be used to confirm current findings. National Center for Biotechnology Information , U. Acta Clin Belg. Published online Dec The host range of an influenza A virus is determined by species-specific interactions between virus and host cell factors.

These include the ability to bind and enter cells, to replicate the viral RNA genome within the host cell nucleus, to evade host restriction factors and innate immune responses and to transmit between individuals. In this Review, we examine the host barriers that influenza A viruses of animals, especially birds, must overcome to initiate a pandemic in humans and describe how, on crossing the species barrier, the virus mutates to establish new interactions with the human host.

Plasma and recombinant-virus samples were analyzed using the ViroSeq system. Each sample was analyzed on three consecutive days at each of three testing laboratories. The sensitivity of mutation detection was The specificity of mutation detection was