Post infection natural immunity, debate and implications for mandatory vaccination https://www.bmj.com/content/374/bmj.n2101 US as of 11th December 2020 https://web.archive.org/web/20210115184811/https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/burden.html US, Natural infection, Feb 2020 to May 2021 0 – 17 26.8 / 73 37% 18 – 49 60.5 / 138 44% 50 – 64 20.4 / 62 32% 65+ 12.3 / 54 23% Total 120.3/ 328 37% Immunological memory to SARS-CoV-2 assessed for up to 8 months after infection https://www.science.org/doi/10.1126/science.abf4063 N = 254 blood samples post infection N = 51 long term follow up Antibodies against SARSCoV- 2 spike and receptor binding domain (RBD) declined moderately over 8 months Memory B cells against SARS-CoV-2 spike increased between 1 month and 8 months after infection. Proportion of subjects positive for CD4+ T cells (92%) remained high at 6 to 8 months after infection. The different types of immunememory each had distinct kinetics, resulting in complex interrelationships over time CONCLUSION Substantial immune memory is generated after COVID-19 About 95% of subjects retained immune memory at ~6 months after infection Circulating antibody titers were not predictive of T cell memory CDC Still recommends a full vaccination dose for all the immune response from vaccination is more predictable antibody responses after infection vary widely by individual June, Peter Marks, Food and Drug Administration’s Center for Biologics Evaluation and Research We do know that the immunity after vaccination is better than the immunity after natural infection generally the immunity after natural infection tends to wane after about 90 days https://www.youtube.com/watch?v=_j8ziaOpl7o It appears from the literature that natural infection provides immunity, but that immunity is seemingly not as strong and may not be as long lasting as that provided by the vaccine UK covid pass guidelines https://www.gov.uk/guidance/nhs-covid-pass#who-can-get-an-nhs-covid-pass-in-england proof of natural immunity shown by a positive PCR test result for COVID-19, lasting for 180 days after the date of the positive test Protection of previous SARS-CoV-2 infection is similar to that of BNT162b2 vaccine protection: A three-month nationwide experience from Israel https://www.medrxiv.org/content/10.1101/2021.04.20.21255670v1.full.pdf Vaccination was highly effective Estimated efficacy for documented infection of 92·8% Hospitalization 94·2% Severe illness 94·4% Death 93·7% Protection from prior SARS-CoV-2 infection Estimated efficacy for documented infection of 94·8% Hospitalization 94·1% Severe illness 96·4% Ministry of Health during summer surge Between 5 July and 3 August (over half a million infected but unvaccinated) Just 1% of weekly new cases were in people who had previously had covid-19 Dvir Aran, biomedical data, Technion–Israel Institute of Technology these numbers look very low the data suggest that the recovered have better protection than people who were vaccinated Systemic side-effects were more common in people previously infected https://www.sciencedirect.com/science/article/pii/S1473309921002243 Large UK study 1·6 times after the first dose of ChAdOx1 nCoV-19 2·9 times after the first dose of BNT162b2 56% more likely to experience a severe side effect that required hospital care Conclusion Public health strategy versus individualised medicine