Take away: COVID-19 infections result in antibodies in almost all cases. These antibodies probably give immunity to future infection for at least some time, although how long is still not known.

The claim: The presence of antibodies to SARS-CoV2 does not guarantee future immunity from future COVID-19 infection.

The evidence: COVID-19 has not been present in the human population long enough to know how long immunity will last. There is some evidence to suggest that having COVID-19 typically leads to antibodies will provide at least some immunity to future infections. The vast majority (>90%) of serious (1-3) and mild (4,5) COVID-19 infections do result in the production of antibodies and it has been found that neutralizing antibodies provide immunity to reinfection in monkeys (6). We do not know how long immunity lasts. The best evidence is from the related coronavirus infections SARS and MERS. SARS and MERS infections result in antibodies that last for at least 1-3 years (7-9).

Source:

1. https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa344/5812996
2. https://erj.ersjournals.com/content/early/2020/05/13/13993003.00763-2020.abstract
3. https://www.nature.com/articles/s41591-020-0897-1)
4. https://www.sciencedirect.com/science/article/pii/S2352396420302905
5. https://www.medrxiv.org/content/10.1101/2020.07.11.20151324v1
6. https://www.biorxiv.org/content/10.1101/2020.03.13.990226v2.abstract
7. https://www.jimmunol.org/content/jimmunol/181/8/5490.full.pdf
8. https://wwwnc.cdc.gov/eid/article/13/10/07-0576_article,
9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5512479/

Take away: The COVID-19 virus (SARS-CoV2) did not exist in 2012, however a related virus was isolated from bats in 2013.

The claim: The same virus that is causing the COVID-19 pandemic existed in miners in 2012.

The evidence:RaTG13, a virus that was isolated from bats by the Wuhan Institute of Virology in 2013 is the closest known relative to SARS-CoV2, the virus that causes COVID-19 (Ge 2016, Zhou 2020). This bat virus is not the same virus as SARS-CoV2, but is closely related (96% identical DNA). The virus was isolated from bats, not humans. However, it was isolated from a cave near where workers the previous year became sick and some died, and may be linked to the illnesses. The SARS-CoV2 virus shows a number of key adaptations that likely makes it much more infectious in humans than the related bat virus (Wrobel, 2020).

Source:

Ge XY, Wang N, Zhang W, Hu B, Li B, Zhang YZ, Zhou JH, Luo CM, Yang XL, Wu LJ, Wang B. Coexistence of multiple coronaviruses in several bat colonies in an abandoned mineshaft. Virologica Sinica. 2016 Feb 1;31(1):31-40.

Zhou P, Yang XL, Wang XG, Hu B, Zhang L, Zhang W, Si HR, Zhu Y, Li B, Huang CL, Chen HD. A pneumonia outbreak associated with a new coronavirus of probable bat origin. nature. 2020 Mar;579(7798):270-3.

Wrobel AG, Benton DJ, Xu P, Roustan C, Martin SR, Rosenthal PB, Skehel JJ, Gamblin SJ. SARS-CoV-2 and bat RaTG13 spike glycoprotein structures inform on virus evolution and furin-cleavage effects. Nature Structural & Molecular Biology. 2020 Aug;27(8):763-7.