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Serological Tests for Covid-19 and the Reopening: Essential or Counterproductive?

We asked Prof. Antonio Giordano about what is creating the confusion that is still a determining factor to save lives at the end of the lockdown

Prof. Antonio Giordano

In Italiano

Antonio Giordano, the Neapolitan scientist, Director of the Sbarro Institute at Temple University and Professor at the University of Siena that our readers know so well from his column in La Voce di New York, “Terra Medica,” has been closely following the evolution of the Covid-19 pandemic. In fact these days he is being interviewed frequently both in the US and Italy by those who seek clarity through the transition from the lockdown to the reopening in New York and elsewhere. We’ve asked Dr. Giordano some questions about serological tests and how antibody testing can help us to determine the evolution of the pandemic.

Why is antibody testing important as governments in Europe and the U.S. move forward with reopening?

 “Antibody testing is key to identify individuals who might have acquired immunity against the virus and also to identify individuals whose antibodies could be used to treat patients severely affected by COVID-19. For as concerns the diagnosis of infection, this is more complex because the humoral, serological, response to the virus occurs in two phases, the first consist of IgM production and the second in which the IgG response is mounted. We still haven’t characterized these phases and we do not know if IgGs confer a long-lasting protection. Therefore there are various issues correlated to the detection of such antibodies:

1. the timing of the testing:  if testing occurs in the early stage of infection antibodies might not be detected;

2. most tests do not reach 100% reliability– they can get close but even 95-97% of specifity /sensitivity means that 3-5% of results will identify FALSE POSITIVES and FALSE NEGATIVES; this , if translated on the whole population, means impressive numbers and consequences;

3. we are still not sure whether commercial tests are specific against SARS-CoV2 or they could recognize other coronaviruses such as the one which caused MERS or even the coronaviruses that cause a simple cold.  In the case of SARS virus, which is a close relative of the COVID virus, a long lasting immunity was seen only for patients that survived the most aggressive manifestations of the disease, so we can imagine that at least COVID patients who were cured of clinically serious cases of the disease have probably long lasting immunity”.

Is it difficult to conduct a reliable, national epidemiological study when every region (or state in the U.S.) is using a different type of antibody test?

 “It is quite obvious that the use of heterogeneous tests with a different degree of reliability will not allow the possibility to confront data. Moreover, let’s say that citizens from a state are provided with an ‘immunity license’ after being tested with a kit that has a 4% false positive detection; what happens when they travel to a state in which testing was performed with a kit that has a 10% false positive detection? Different states will adopt different safety measures based on their own rates.

The risk that ‘immunity licences’ could lead to discrimination is also higher: employeers or insurance companies might favour people who can prove to be immune.

It is intuitive that more homogeneous strategies should be adopted nationally and possibly worldwide.

Such immunity passports or “risk-free certificates have been the subject of an alert raised on April 24 by the WHO. At present, there is not enough evidence on the effectiveness of antibody-mediated immunity to protect from another infection. The WHO concerns relate to the fact that individuals  who assume that they are immune to a second infection because they have received a positive test result may ignore public health advice”.

Prof. Antonio Giordano with colleagues and students at the Sbarro Institute of Philadelphia

The last time we spoke, there were still many doubts as to the reliability of the antibody tests on the market. Has the reliability and efficacy of these tests been getting better?

Just three days ago the UK approved a test developed by the Roche giant which claims a specificity greater than 99.8% and a sensitivity of 100%.

It is clear that the more we get to know the virus and the host response to the infection, the more will be able to develop more precise tests”.

Do you think the increased competitiveness of this market will lead to better testing overall? Or would it have the opposite effect as companies might be pressured to rush out products that aren’t as proven? What about political pressure to rush for a vaccine?

The hunt for tests and vaccines will indeed help to accelerate research and provide better tools to prevent, detect and cure the disease. We definitively need to act together –meaning the whole scientific community– to make sure that each research is critically and fairly assessed by the peers. Whereas governments should act together in concert with pharma consortia to avoid speculation and that money interests prevails on the global health rights”.

What lessons do you think the U.S. could learn from what is happening in Italy with regard to this rapidly growing testing market?

“The Italian national health system is highly fragmented  across 21 regions which have most of the administrative and organizational power and a weak strategic leadership of the government. Moreover the national health system has suffered in the past decades financial cuts of over €37 billion along with a progressive privatization of health-care services. All this contributed to poorly effective intervention in tackling the Covid-19 emergency especially in the North, which had the highest burden.

It should be mandatory that all strategies to counteract the epidemic, including antibody testing, are put in place by the central government. Ideally, since the world has become “a smaller place” due to travel and trade and conjoined economies, the strategies should be coordinated at the continent/sub-continent level (e.g. Western Europe, North America, South America, etc.).  This approach would have the highest probability of success against present and future microbiological threats”.


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