Hello!

The formation of antibodies after the transferred covid-19 infection depends on the immunological reactivity of the organism. Antibodies may not be formed if a human's infection was asymptomatic, with a mild form of infection, if a person has reduced immunity, has chronic, oncological, infectious, allergic, immunodeficient diseases (AIDS), or the patient is taking immunosuppressants (corticosteroids, chemotherapy) or undergoing radiation or chemotherapy.

I have two persons from my husband family as example for this case

Dear Dr. Kadhim!

This is a very important question to consider. I found articles that give some clues but further research is needed:

Weisberg, S.P., Connors, T.J., Zhu, Y. et al. Distinct antibody responses to SARS-CoV-2 in children and adults across the COVID-19 clinical spectrum. Nat Immunol (2020)., Open Access: https://www.nature.com/articles/s41590-020-00826-9

Qing Lei et al. (2020). Antibody dynamics to SARS‐CoV‐2 in asymptomatic COVID‐19 infections, European Journal of Allergy and Clinical Immunology, 10 October 2020, Citation: "Our findings might have important implications for the definition of asymptomatic COVID‐19 infections, diagnosis, serological survey, public health, and immunization strategies. ", Open Access:

Article Antibody dynamics to SARS-CoV-2 in asymptomatic COVID-19 infections

Yours sincerely, Bulcsu Szekely

I agree on the possibility that there may be an impact on the phenomenon due to the individual's immune competence.

Memory of the cell-mediated immune response (not based on antibodies production) may be involved. Unfortunately, we are unable to measure the extent of the cell-mediated immune memory

we are only able to measure the antibody titre in the body by the tests we have. we have not been able to measure the level of memory in these cells.

Why a patient with confirmed COVID-19 has no SARS-CoV-2 antibodies?

It all depends on various factors like the immunological response of the COVID-19 infected person, whether the patient was symptomatic or asymptomatic, the timing of the antibody testing, and the sensitivity of the test-kits used to check the antibodies:

For example in this early study (1), forty percent of asymptomatic individuals became seronegative and 12.9% of the symptomatic group became negative for IgG in the early convalescent phase.

Another article discusses negative tests in confirmed COVID-19 patients (2)

1. Article Clinical and immunological assessment of asymptomatic SARS-C...

2. Article COVID-19 confirmed patients with negative antibodies results

The answer to this question requires that we first confirm that all asymptomatic patients didn't develop antibodies.

Individual immune system differences and a whole lot other factors may affect antibody development.

Most of our patients do not develop antibodies, specially if they had a mild illness. Literature shows evidence of no antibodies and waning antibodies. Both these factors make reinfention a possibility

However new articles suggest T cell medciated immunity which is difficult to measure or monitor

we need more research in this area.

Because some of this patients already has equal antibodies of IgG or IgM.

There have been cases where the persons who have recovered from COVID have the presence of antibodies which wane of with time and then the person gets reinfected for the second time.

In case of asymptomatic COVID-19 individuals, the viruses probably rest in URT and cannot proceed further downwards because of the INNATE IMMUNITY based on the genetic and constitutional make-up of the individuals. In order to produce antibodies viruses need to come in contact with the IMMUNOCYTES which are not occurring in these cases. So genetic factors of the humans probably play an important role for creating asymptomatic cases. Again, for production of ANTIBODIES some days are required which are not happening in these individuals because the persons become virus-free by that time. So there are no S/S and also therefore no ANTIBODY production. The above is a HYPOTHETICAL possibility.

waiting for the best answer.

Message from Astrobiology: first global foci are linked geographically.

We have answer why.

Thank you for their answers

An interesting trend in India is a decline in the active and incident cases along with rising seroprevalence. Why the seroprevalence did not rise in the previous 2 peaks of cases(rather had a fall), and why in this 3rd peak it is nearly 50% is still unclear.

But definitely, rising seroprevalence and vaccination can help in achieving herd immunity soon

Despite high antibody title, many getting covid 19 again.

Most likely mutated virus.

No protection from previous infection or vaccine

How does one determine if antibody will provide immunity? (as in example of HIV, even having antibodies does nothing much to change the course of the disease – similar with hepC).

Protection to reinfection to SARS-CoV-2 after COVID-19 infection or vaccinations depends on protective antibodies and immune memory to the virus

Protection from SARS-CoV-2 reinfection after recovery from COVID-19 depends on the interplay of the formation of antibodies and the immune memory induced by previous COVID-19 infection or after COVID-19 vaccine.

Whereas the antibody titers may wane after COVID-19 infection or vaccination, longer lasting immunity may depend on robustness of immunological memory after re-exposure to SARS-CoV-2.

To understand this relationship please have a look at these articles:

1. Immune Memory after COVID-19

https://hms.harvard.edu/news/immune-memory-after-covid-19

2. Article Immunological memory to SARS-CoV-2 assessed for up to 8 mont...

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