Good news about protection against COVID-19 (SARS-CoV-2) variant viruses

A preprint paper yesterday provided evidence that cellular immunity that develops after COVID-19 infection protects against worrisome SARS-CoV-2 variant viruses. This is a different type of immunity from most prior studies which have only looked at blood antibody (protein) immunity. These lymphocyte killer responses are particularly important immunity for viral infections.

Cellular immunity involves recognition of small peptide sequences in the spike protein of the virus. The T cells that recognize these sequencs can be activated to directly kill cells infected with virus. This can control the infection even in the absence of antibodies that neutralize the virus. 

Cellular Immunity Produced Killer T cells that can kill virally infected cells. This can control a viral infection.

Clinically, it appears that cellular immunity is more important in protecting against COVID-19 because people without antibodies have survived SARS CoV-2 infection, but individuals with defective cellular immunity do not, even when given antibody against the virus. 

Variants have changes in their gene sequence that lead to alterations in the structure of the spike protein. Antibodies can be defeated by a few small changes in protein sequence seen in variant viruses. Cellular immunity, because it recognizes multiple sites within a protein, is not as easily defeated.  

Single amino acid code sequence of part of SARS-CoV-2 virus spike protein. Most human T cell recognition sites in the spike protein(green letters) are not disrupted by amino acid changes in variant viruses(orange letters).

When immune lymphocytes are activated by variant viruses, then new immunity can be generated and eventually neutralize the virus. New antibodies to the modified virus can also be generated.

If immunity after infection can provide this type of protection, it should also be seen after two doses of a vaccine against SARS-CoV-2. This provides real hope that the current vaccines should protect us against all forms of COVID-19 including the variant viruses in the U.K., South Africa, and Brazil that have raised concern.  

Published by jbakerjrblog

Immunologist, former Army MD, former head of allergy and clinical immunology at University of Michigan, vaccine developer and opinionated guy.

8 thoughts on “Good news about protection against COVID-19 (SARS-CoV-2) variant viruses

  1. Dr. Baker finally some positive news regarding the variants!!! Thank you. I am now 17 days out from my 2nd dose of the Pfizer vaccine and still not sure if I can hug my grandbabies. I have not done that in 13 months. The variants have made me paranoid about letting anyone in the house to fix all of the things that need repair. I think I still have a 6% chance to contract COVID right? Since 10-30% of those infected can experience long haul issues- I don’t want anything to do with SARS-COV2! Am I wearing a mask still to protect others or myself? I have so any questions and it doesn’t seem like we are getting clear answers. Thank you for always being fact based!

    Liked by 1 person

  2. Good Morning…
    What are your thoughts about pregnant women receiving the COVID 19 vaccine?
    Can you point me in the correct direction of articles that may discuss this decision?
    Thank you sooo much!

    Liked by 1 person

  3. Does this data suggest that vaccinated individuals are better protected from variants? If I’m understanding that to be the case. HOW would a gated community respond to reopening with this new info? Should members and guests be required to see Vaccination Proof to use indoor facilities? Do non-vaccinated members/ guests put vaccinated members at risk of being exposed to a unknown variant? Thanks..

    Liked by 1 person

    1. the vaccinated should be safe regardless, but it would be important to encourage everyone to get vaccinated. They are a source of infection for children and people with immune problems.


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