I’ve watched John Campbell review all things related to COVID-19 since the beginning of the pandemic. He has proven to be 100% unbiased and willing to represent the evidence as well as he understands it.

His first video on Coronavirus aired Jan 26, 2020. He now has 1.2M viewers on YouTube - with endless videos, one or two per day, he has covered nearly every aspect of COVID-19 and SARS-CoV-2.

In this video, he reviews the scientific evidence of natural immunity, which he says “seems good and long-lasting and cheap, lots of evidence below.”

He expansion collection of links and annotations are provided below for those looking for resources on evidence of natural immunity.

https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00676-9/fulltext

Biological studies

Dan et al (2021) Science, Immunological memory to SARS-CoV-2 assessed for up to 8 months after infection.

https://www.science.org/doi/full/10.1126/science.abf4063

95% of participants tested retained immune memory at about 6 months after having COVID-19

More than 90% of participants had CD4+ T-cell memory at 1 month,

and 6–8 months after having COVID-19

Wang et al (2021) Science, Ultrapotent antibodies against diverse and highly transmissible SARS-CoV-2 variants

https://www.science.org/doi/full/10.1126/science.abh1766

Previous SARS-CoV-2 infection, with an ancestral variant produce antibodies that cross-neutralize emerging variants of concern with high potency

Epidemiological studies

Hansen et al (2021) Lancet, Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00575-4/fulltext

People who had had COVID-19 previously were around 80·5% protected against reinfection

Pilz et al (2021) European Journal of Clinical Investigation, SARS-CoV-2 re-infection risk in Austria

https://onlinelibrary.wiley.com/doi/full/10.1111/eci.13520

Sheehan et al (2021) Clinical Infectious Diseases, Reinfection rates among patients who previously tested positive for COVID-19: a retrospective cohort study

https://academic.oup.com/cid/article/73/10/1882/6170939

Shrestha et al (2021) Preprint, Necessity of COVID-19 vaccination in previously infected individuals

https://www.medrxiv.org/content/10.1101/2021.06.01.21258176v3

Retrospective cohort study in the USA,

People who had had COVID-19 previously were 100% protected against reinfection

Gazit et al (2021) Preprint, Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections

https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v1

Kojima et al (2021) Preprint, Incidence of severe acute respiratory syndrome coronavirus-2 infection among previously infected or vaccinated employees

https://www.medrxiv.org/content/10.1101/2021.07.03.21259976v2

Laboratory staff routinely screened for SARS-CoV-2, people who had had COVID-19 previously were 100% protected against reinfection

Clinical studies

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00675-9/fulltext

Large, multicenter, prospective cohort study

Previous COVID-19 diagnosis, 84% decreased risk of infection

Letizia et al (2021) Lancet, Respiratory Medicine, SARS-CoV-2 seropositivity and subsequent infection risk in healthy young adults: a prospective cohort study

https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(21)00158-2/fulltext

Prospective cohort of US Marines.

Seropositive young adults were 82% protected against reinfection

Adnan et al (2021) Clinical Infectious Diseases, Reinfection With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Patients Undergoing Serial Laboratory Testing

https://academic.oup.com/cid/article/74/2/294/6251701

N = 9,119, serial tests

Reinfection rates, 0.7%

So

Risk of repeat SARS-CoV-2 infection decreased by 80·5–100% among those who had had COVID-19

Protection from reinfection is strong and persists for more than 10 months of follow-up, (Hansen et al 2021 Lancet)

Turner, et al Nature, SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans

https://www.nature.com/articles/s41586-021-03647-4?amp%3Bcode=7bafb609-23c2-4665-804b

Madhuumita et al, Plos One, T cell response to SARS-CoV-2 infection in humans: A systematic review

https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0245532

SARS-CoV-2 infection induces specific and durable T-cell immunity,

Nina et al, (2020) Nature, SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls

https://www.nature.com/articles/s41586-020-2550-z?flip=true

Memory B-cell response to SARS-CoV-2 evolves between 1·3 and 6·2 months after infection, which is consistent with longer-term protection

Some people who have recovered from COVID-19 might not benefit from COVID-19 vaccination

https://www.medrxiv.org/content/10.1101/2021.04.20.21255670v1

One study found that previous COVID-19 was associated with increased adverse events following vaccination with Pfizer

https://www.journalofinfection.com/article/S0163-4453(21)00277-2/fulltext

In Switzerland, proof of recovered infection, in the past 12 months are considered equally protected as fully vaccinated,

https://www.schengenvisainfo.com/news/switzerland-plans-to-extend-covid-certificate-requirement-until-mid-november/

Thank you, John!

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John Campbell's List of Studies On Natural…