A recently released study by researchers based in Italy & the UK assessed IgG titers over 18 months in patients who had recovered from Covid infections during March 2020. The study also investigated the impact of two doses of the Pfizer vaccination on the antibody titers of these patients as compared to those patients who had not received any dose of the vaccine.
This is one of the longest studies ever done on the IgG antibody titers.
The study shows that vaccination can elicit a more specific and higher magnitude response focused on the spike-receptor binding domain (S-RBD) instead of the Nucleocapsid (NCP) as compared to natural infection. The antibody titers increased rapidly post-vaccination, but the rise was short-lived, which explains the importance of boosters. The IgG titers were reported to increase 161 times while the IgM titers increased by an amount of 0.773.
However, unvaccinated recovered individuals were found to test positive for anti-S-RBD antibodies 18 months post-infection. No cases of reinfection were reported in these individuals despite the emergence of multiple mutant strains that brought about several waves of infection. Most recovered individuals also tested positive for anti-NCP antibodies at 18 months post-infection.Therefore, the current study demonstrates that immunity conferred by SARS-CoV-2 infection lasted longer as compared to vaccination.
The figure above shows the modeling results to determine the effect of vaccination on antibody titers (IgM and IgG) in recovered subjects. NCP has lower IgM, by amount of 0.324, relative to spike. Similarly, NCP has a lower IgG than spike by a factor of 0.119.
A double-dose vaccination with BNT162b2 in recovered individuals induced an enormous but short-lived increase in antibody titers. While the IgM titers increased by an amount of 0.773, the IgG titers increased 161 times.
PS: Sadly the study involved only a limited number of participants.
Note: The nucleocapsid protein (NCP) of the SARS-CoV-2 is considered a biomarker associated with natural exposure. Since this NCP is not present in spike-based vaccines, there is no vaccine-induced response against it in vaccinated individuals. Testing for anti-NCP could be an important tool to analyze the type of existing immunity in an individual (vaccine-induced/ natural/ hybrid). Moreover, Vaccinated individuals who were previously exposed usually test positive for antibodies against NCP (hybrid immunity) while the vaccinated individuals who have never been exposed lack anti-NCP antibodies (vaccine-induced immunity).
PPS: When this study was done there was no Omicron. Just a few hour ago a UK study confirmed that over 66% of Omicron cases are reinfections. Also 50% of the cases were with those who were fully vaccinated.
This is one of the longest studies ever done on the IgG antibody titers.
The study shows that vaccination can elicit a more specific and higher magnitude response focused on the spike-receptor binding domain (S-RBD) instead of the Nucleocapsid (NCP) as compared to natural infection. The antibody titers increased rapidly post-vaccination, but the rise was short-lived, which explains the importance of boosters. The IgG titers were reported to increase 161 times while the IgM titers increased by an amount of 0.773.
However, unvaccinated recovered individuals were found to test positive for anti-S-RBD antibodies 18 months post-infection. No cases of reinfection were reported in these individuals despite the emergence of multiple mutant strains that brought about several waves of infection. Most recovered individuals also tested positive for anti-NCP antibodies at 18 months post-infection.Therefore, the current study demonstrates that immunity conferred by SARS-CoV-2 infection lasted longer as compared to vaccination.
The figure above shows the modeling results to determine the effect of vaccination on antibody titers (IgM and IgG) in recovered subjects. NCP has lower IgM, by amount of 0.324, relative to spike. Similarly, NCP has a lower IgG than spike by a factor of 0.119.
A double-dose vaccination with BNT162b2 in recovered individuals induced an enormous but short-lived increase in antibody titers. While the IgM titers increased by an amount of 0.773, the IgG titers increased 161 times.
PS: Sadly the study involved only a limited number of participants.
Note: The nucleocapsid protein (NCP) of the SARS-CoV-2 is considered a biomarker associated with natural exposure. Since this NCP is not present in spike-based vaccines, there is no vaccine-induced response against it in vaccinated individuals. Testing for anti-NCP could be an important tool to analyze the type of existing immunity in an individual (vaccine-induced/ natural/ hybrid). Moreover, Vaccinated individuals who were previously exposed usually test positive for antibodies against NCP (hybrid immunity) while the vaccinated individuals who have never been exposed lack anti-NCP antibodies (vaccine-induced immunity).
PPS: When this study was done there was no Omicron. Just a few hour ago a UK study confirmed that over 66% of Omicron cases are reinfections. Also 50% of the cases were with those who were fully vaccinated.
