Diagnostic Value of New COVID-19 Antibodies Testing Among Laboratory Healthcare Workers

In December 2019, a new corona virus (CoV) emerged in China to cause an acute respiratory
disease known as corona virus disease 19 (COVID-19).The virus was identified to be a
betacoronavirus related to severe acute respiratory syndrome corona virus (SARS-CoV) and
thus, was named SARS-CoV-2 .

New Covid-19 virus is the third known corona virus to cross the species barrier and cause
severe respiratory infections in humans following SARS-CoV in 2003 and Middle East
respiratory syndrome in 2012, yet with pandemic spread compared to the earlier two. In
comparison, to SARS-CoV and MERS-CoV, COVID-19 virus exhibits faster human-to-human
transmission.

The World Health Organization (WHO) declared COVID-19 outbreak as a world pandemic on 12th
March 2020. Diagnosis of suspected cases is confirmed by molecular techniques (real-time
PCR), using respiratory samples. Serology tests are easier to perform than molecular testing,
but their utility may be limited by the performance and the fact that antibodies appear later
during the disease course.

In the absence of a vaccine, public health authorities in several countries has shown that
shutdowns can only be safely ended if a systematic "test and trace" program is put in place
to control the spread of the virus which depends on the widespread availability of mass
diagnostic testing.

From this point of view, detecting carriers of the virus in asymptomatic laboratory health
care worker is fundamental to response efforts. It ensures the quarantine of COVID-19
patients to prevent local spread and more broadly informs national response measures.

The main route of transmission is person-to-person spread. A vulnerable cohort for infection
due to frequent and close contact to COVID-19 patients are healthcare workers. To avoid
patient-to-staff transmission adherence to strict hygiene standards is important. The
infection with the SARS-CoV-2 usually leads to seroconversion 11-14 days after the first
symptoms . However, due to asymptomatic and oligosymptomatic infections testing only
symptomatic individuals can lead to a significant underestimation of the SARS-CoV-2
seroprevalence Day,.

Antibody testing is multipurpose: these serological assays are of critical importance to
determine seroprevalence, previous exposure and identify highly reactive human donors for the
generation of convalescent serum as therapeutic. They will support contact tracing and
screening of health care workers to identify those who are already immune. How many people
really got infected, in how many did the virus escape the PCR diagnosis, and for what
reasons, how many patients are asymptomatic, and what is the real mortality rate in a defined
population? Only with comprehensive serology testing (and well-planned epidemiological
studies) will we be able to answer these questions and reduce the ubiquitous undisclosed
number in the current calculations. Several investigations are already underway in a wide
variety of locations worldwide