Patients who recover from COVID-19 or remain asymptomatic despite a definite contact with a SARS-CoV-2 infection proven by testing have been shown to produce specific IgM and IgG antibodies against this virus. The presence of IgG antibodies proven by a reliable test in a person usually means that such a person is immune. (1). FDA has already approved such a test (2)
Many countries e.g USA and Italy are considering doing these SARS-CoV-2 specific antibody tests in the population to know the immune status.
The antibody testing will be able to:
1. Know the exposure of population to novel coronavirus (SARS-CoV-2) and immune status.
2. Allowing immune people to start working.
3. Selecting immune healthcare workers to look after COVID-19 cases.
4. Using plasma from immune people for treating COVID-19 patients.
What is your opinion?
1. https://www.researchgate.net/post/What_is_the_duration_of_immunity_after_recovery_from_ COVID-19
2. https://www.whec.com/coronavirus/fda-approves-covid-19-antibody-test-from-rochester/5700985/?cat=565
How Covid-19 immunity testing can help people get back to work
https://www.vox.com/2020/3/30/21186822/immunity-to-covid-19-test-coronavirus-rt-pcr-antibody
Well to take plasma from immune people,but there are large population now.It will be a novel discovery if we could understand the genetic encoding human immunization and will be very promising to clone such genes in microorganisms such as bacteria or yeasts.
90% of the patients may have undocumented (possibly asymptomatic) COVID-19 infection by antibody testing.
Now mass testing of people in Germany and New York, USA has started.
Initial results of antibody tests in New York indicate that compared to documented positive COVID-19 patients, the number of patients exposed to the virus are 10 times more. This indicates that undocumented patients are 1o times the documented patients.
https://www.ny1.com/nyc/all-boroughs/news/2020/04/23/governor-cuomo-daily-coronavirus-update-with-first-antibody-test-results
It’s unclear what antibody levels provide the best defense.
People with lower antibody levels could be more at risk for reinfection, but you might also be able to still ramp up a rapid [immune] response and prevent the virus from spreading deeper into the lungs.
But even people with protective antibodies aren’t necessarily bulletproof. Some people may be completely protected against infection, a state known as sterilizing immunity, which is hard to achieve. Others may get infected again, but have mild or no symptoms.
We would have to follow recovered COVID-19 patients who are antibody-positive for a long period of time and see if any of them become infected again.
Researchers also don’t know how long SARS-CoV-2 antibodies stick around. Some viruses, such as measles, can trigger protection that lasts a lifetime. Defenses against other viruses can wane over time. Studies suggest that protection against coronaviruses that cause the cold can last for about a year. Antibodies for the original SARS virus, on the other hand, slowly vanished over a few years. Since SARS no longer infects people, it’s unclear whether a lack of antibodies means lack of protection. And because the new coronavirus has been infecting people for only a few months, it’s still unknown whether it will behave similarly.
Despite the unknowns surrounding antibodies and SARS-CoV-2, some countries including the United States are considering using antibody tests as a stepping stone to provide so-called “immunity certificates” to people who test positive that would allow them to reenter society or return to work. Some experts, however, are skeptical.
We don’t know that having antibodies necessarily means you’re immune, so it could give people a false sense of security about how safe they are. And, according to the WHO, that could increase the risks that the virus will continue to spread.
Immunity passport : A myth or reality?
Based on antibody testing, some of the countries (USA, UK, Australia, Germany) are thinking of an immunity passport to people who are showing evidence of exposure to SARS-CoV-2 (symptomatic or asymptomatic). People with these immunity passports would be able to travel and can work (1,2).
However, WHO (3) is not in favour of this idea of Immunity passport until further studies of the implication of anti-body based immunity for COVID-19.
1. Article Immunity Passports: A "New" Old Idea With Baggage
2. Article Ethical Implementation of ‘Immunity Passports’ during the CO...
3. https://apps.who.int/iris/handle/10665/331866
A NEW STUDY may partly explain why the immunity by exposure to COVID-19 or any vaccine may not be working, because the immunity is strain specific.
The Conclusion of the study reads:
“The mutation Spike D614G is of urgent concern; it began spreading in Europe in early February, and when introduced to new regions it rapidly becomes the dominant form. Also, we present evidence of recombination between locally circulating strains, indicative of multiple strain infections. These finding have important implications for SARS-CoV-2 transmission, pathogenesis and immune interventions.”
https://www.biorxiv.org/content/10.1101/2020.04.29.069054v1
Lets wait for the results of the phase 3 trials on COVID-19 expected to be released in October 2020.
Yes, people who are asymptomatic and had documentary evidence of having protective immunity against SARS-cov2 by showing an increased titre of IgG must be allowed to join their routine pursuits. Having said that, they must be encouraged for plasma donation in the plasma bank as a social responsibility for fellow citizens.
A single dose of COVID-19 vaccination is recommended for those who have had a documented COVID-19 infection, according to this study:
Preprint Robust spike antibody responses and increased reactogenicity...
