Basic Covid Facts

Updated: August 2024

  1. We are still in the COVID-19 Pandemic. 1 2 In the United States alone, at least hundreds die per week from COVID, 3 and there are hundreds of thousands to millions of new COVID cases per day. 4 5
  2. Masks are extremely effective at reducing the spread of COVID-19. 6 7 8 9
    Respirator/tight-fitting masks such as N95s and KN95s are much more effective than cloth and surgical masks. 10 11 Universal masking with high quality masks is much more effective than one-way masking. 12
  3. Long COVID develops in 10% to 30% or more of people who get COVID, even in mild cases and even among those who are vaccinated. It consists of often severe symptoms lasting at least 3 months or indefinitely longer. 13 Long COVID is causing many to miss extensive work time. 14 Some people infected years ago still struggle with Long COVID which severely impacts every aspect of their lives; you can read about some of their experiences at #LongCovid.
  4. Immunocompromised, disabled, and elderly people are among those substantially more likely to get very sick or die from COVID. 15 16 These at-risk people disproportionately experience the worst effects of COVID and find themselves unable to safely do necessary activities like going to the doctor and grocery store without widespread masking and improved air ventilation.
  5. COVID can cause long-term damage to the immune system after infection, making you more likely to get sick from COVID again or other diseases. 17 18 19 20 Newer variants do not provide significant immunity against further COVID infections. 21 The idea that getting sick strengthens your immune system is false. 22
  6. COVID is not just a respiratory illness, it can have negative long-term impacts on all areas of your body, even if vaccinated and even from mild infection. 23
    1. Risk of heart disease substantially increases after COVID infection. 24 25
    2.  COVID can have a large negative impact on your brain, causing issues like brain fog and significant drops in IQ scores. 26 27 28 29 30
    3.  COVID can accelerate biological aging. 31 And there are many, many more studies that have been done on COVID’s impact on all parts of the body.
  7. Repeat COVID infections are common, even among those vaccinated, and likely put you at greater risk of severe disease and Long COVID. 32 You can be reinfected within a month of initial infection. 33
  8. While our current vaccines are somewhat effective in lowering the risk of severe disease and death, they do not significantly prevent infection from the latest variants. 34 Vaccines do not prevent you from infecting others with COVID. 35 In the United States, a majority of people who die are vaccinated. 36
  9. COVID is airborne, 37 meaning it spreads not just from coughing and sneezing, but through the air where it can spread over long distances.
  10. Cleaning indoor air and improved air ventilation can reduce the spread of COVID in indoor spaces. 38 HEPA filters can continuously remove COVID from the air. 39
  11. Asymptomatic infections do spread COVID and account for half of all COVID transmission. 40
  12. Rapid tests struggle to detect the latest variants 41 42 43 and multiple tests are needed to confirm whether you have COVID. 
  13. Once infected, you can be very infectious for 8-10 days after initial symptoms start. 44 45 46
  14. Newer variants are not milder than previous COVID variants. 47
  15. Rest is very important in helping your body recover from a COVID infection. 48 An extended recovery period (maybe even several months) before resuming exercise can reduce your chances of the worst long-term outcomes from COVID. 49
  1. World Health Organization. (n.d.). Coronavirus disease (covid-19) pandemic. World Health Organization. https://www.who.int/europe/emergencies/situations/covid-19
  2. Bartels, M. (2024, February 5). Rampant covid poses new challenges in the fifth year of the pandemic. Scientific American. https://www.scientificamerican.com/article/rampant-covid-poses-new-challenges-in-the-fifth-year-of-the-pandemic/
  3. “CDC Covid Data Tracker.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, https://covid.cdc.gov/covid-data-tracker/#trends_weeklydeaths_select_00
  4. Pandemic mitigation collaborative – COVID-19 forecasting model. (n.d.). https://pmc19.com/data/
  5. COVID-19: Wastewater Surveillance. CDC Covid Data tracker. Centers for Disease Control and Prevention. https://covid.cdc.gov/covid-data-tracker/#wastewater-surveillance
  6. Greenhalgh T, MacIntyre CR, Baker MG, Bhattacharjee S, Chughtai AA, Fisman D, Kunasekaran M, Kvalsvig A, Lupton D, Oliver M, Tawfiq E, Ungrin M, Vipond J.2024.Masks and respirators for prevention of respiratory infections: a state of the science review. Clin Microbiol Rev 37:e00124-23. https://doi.org/10.1128/cmr.00124-23
  7. “Largest Study of Its Kind Finds Face Masks Reduce COVID-19.” UC Berkeley Public Health, 8 Sept. 2021, https://publichealth.berkeley.edu/covid-19/largest-study-of-its-kind-finds-face-masks-reduce-covid-19/.
  8. Boutzoukas, Angelique E., et al. “School Masking Policies and Secondary SARS-COV-2 Transmission.” American Academy of Pediatrics, American Academy of Pediatrics, 20 May 2022, https://doi.org/10.1542/peds.2022-056687
  9. “Masks Are Effective but Here’s How a Study from a Respected Group Was Misinterpreted to Say They Weren’t.” ABC News, ABC News Network, https://abcnews.go.com/Health/masks-effective-study-respected-group-misinterpreted/story?id=97846561.
  10. Duncan, Scott et al. “The protective performance of reusable cloth face masks, disposable procedure masks, KN95 masks and N95 respirators: Filtration and total inward leakage.” PloS one vol. 16,10 e0258191. 6 Oct. 2021, doi:10.1371/journal.pone.0258191 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8494377/
  11. University of Maryland. (2024, August 9). N95 masks nearly perfect at blocking COVID, UMD study shows. Maryland Today. https://today.umd.edu/n95-masks-nearly-perfect-at-blocking-covid-umd-study-shows
  12. An Upper Bound on One-to-One Exposure to Infectious Human … – PNAS. https://www.pnas.org/doi/10.1073/pnas.2110117118.
  13. Davis, Hannah E., et al. “Long Covid: Major Findings, Mechanisms and Recommendations.” Nature News, Nature Publishing Group, 13 Jan. 2023, https://www.nature.com/articles/s41579-022-00846-2.
  14. Sick days: Assessing the economic costs of long COVID. (2024, August 15). YaleNews. https://news.yale.edu/2024/08/15/sick-days-assessing-economic-costs-long-covid
  15. “People Who Are Immunocompromised.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/people-who-are-immunocompromised.html.
  16. “Covid-19 Risks and Information for Older Adults.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 22 Feb. 2023, https://www.cdc.gov/aging/covid19/index.html.
  17. Ewing, Andrew. “Covid-19 and Immune Dysregulation, a Summary and Resource.” WHN, 15 Mar. 2023, https://whn.global/scientific/covid19-immune-dysregulation/.
  18. “SARS-COV-2 Infection Weakens Immune-Cell Response to Vaccination.” National Institute of Allergy and Infectious Diseases, U.S. Department of Health and Human Services, https://www.niaid.nih.gov/news-events/sars-cov-2-infection-weakens-immune-cell-response-vaccination.
  19. Kratzer, B., Gattinger, P., Trapin, D., Ettel, P., Körmöczi, U., Rottal, A., Stieger, R. B., Sehgal, A. N. A., Feichter, M., Borochova, K., Tulaeva, I., Grabmeier‐Pfistershammer, K., Tauber, P. A., Perkmann, T., Fae, I., Wenda, S., Kundi, M., Fischer, G. F., Valenta, R., & Pickl, W. F. (2024). Differential decline of SARS‐CoV‐2‐specific antibody levels, innate and adaptive immune cells, and shift of Th1/inflammatory to Th2 serum cytokine levels long after first COVID‐19. Allergy. https://doi.org/10.1111/all.16210
  20. Davitt E, Davitt C, Mazer MB, Areti SS, Hotchkiss RS, Remy KE. COVID-19 disease and immune dysregulation. Best Pract Res Clin Haematol. 2022 Sep;35(3):101401. doi: 10.1016/j.beha.2022.101401. Epub 2022 Oct 15. PMID: 36494149; PMCID: PMC9568269. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9568269/
  21. Wang, J., Lan, T., Wei, Y. et al. Omicron variant: a booster depending on infection histories. Sig Transduct Target Ther 8, 6 (2023). https://doi.org/10.1038/s41392-022-01279-2
  22. Farah, Troy. “‘Immunity Debt’ Is Not a Thing.” Salon, Salon.com, 3 Dec. 2022, https://www.salon.com/2022/12/04/does-your-immune-system-need-a-workout-the-science-behind-immunity-debt-explained/.
  23. “Covid-19: Long-Term Effects.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 28 June 2022, https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-long-term-effects/art-20490351.
  24. Han, L., Zhao, S., Li, S. et al. Excess cardiovascular mortality across multiple COVID-19 waves in the United States from March 2020 to March 2022. Nat Cardiovasc Res 2, 322–333 (2023). https://doi.org/10.1038/s44161-023-00220-2
  25. Severe lung infection during COVID-19 can cause damage to the heart. (2024, June 5). National Institutes of Health (NIH). https://www.nih.gov/news-events/news-releases/severe-lung-infection-during-covid-19-can-cause-damage-heart
  26. Al-Aly, Z. (n.d.). Mounting research shows that COVID-19 leaves its mark on the brain, including significant drops in IQ scores. The Conversation. https://theconversation.com/mounting-research-shows-that-covid-19-leaves-its-mark-on-the-brain-including-significant-drops-in-iq-scores-224216
  27. SciTechDaily. (2024, August 23). The Invisible Damage: How COVID rewires our brains. SciTechDaily. https://scitechdaily.com/the-invisible-damage-how-covid-rewires-our-brains/
  28. Kausel, L., Figueroa-Vargas, A., Zamorano, F. et al. Patients recovering from COVID-19 who presented with anosmia during their acute episode have behavioral, functional, and structural brain alterations. Sci Rep 14, 19049 (2024). https://doi.org/10.1038/s41598-024-69772-y
  29. Brain effects of mild COVID-19 in healthy young adults: A pilot study. Lipton, Michael L. et al. Heliyon, Volume 10, Issue 15, e34764 https://www.cell.com/heliyon/fulltext/S2405-8440%2824%2910795-5
  30. Proal, A. (2024, July 27). “Multiple hit” model shows that COVID protein potentiates subsequent infection-related neuroinflammation and other physiological problems. PolyBio Research Foundation. https://polybio.org/multiple-hit-model-shows-that-covid-protein-potentiates-subsequent-infection-related-neuroinflammation-and-other-physiological-problems/
  31. Cao, X., Li, W., Wang, T. et al. Accelerated biological aging in COVID-19 patients. Nat Commun 13, 2135 (2022). https://doi.org/10.1038/s41467-022-29801-8
  32. Schmidt, Charles. “Do Repeat COVID Infections Increase the Risk of Severe Disease or Long Covid?” Scientific American, Scientific American, 15 Feb. 2023, https://www.scientificamerican.com/article/do-repeat-covid-infections-increase-the-risk-of-severe-disease-or-long-covid/.
  33. Girardi, V., Gularte, J.S., Demoliner, M. et al. Reinfection by SARS-CoV-2 by divergent Omicron sublineages, 16 days apart. Braz J Microbiol 54, 1847–1851 (2023). https://doi.org/10.1007/s42770-023-01018-x
  34. (2023) Bivalent Covid-19 Vaccines. N Engl J Med 388:12, 1151-1152. https://www.nejm.org/doi/full/10.1056/NEJMc2214293.
  35. “Monitoring COVID-19 Cases, Hospitalizations, and Deaths by Vaccination Status.” Centers for Disease Control and Prevention, https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/monitoring.html.
  36. “Why Do Vaccinated People Represent Most Covid-19 Deaths Right Now?” KFF, 30 Nov. 2022, https://www.kff.org/policy-watch/why-do-vaccinated-people-represent-most-covid-19-deaths-right-now/.
  37. “Indoor Air and Coronavirus (COVID-19).” EPA, Environmental Protection Agency, https://www.epa.gov/coronavirus/indoor-air-and-coronavirus-covid-19.
  38. Lewis, Tanya. “We Need to Improve Indoor Air Quality: Here’s How and Why.” Scientific American, Scientific American, 8 June 2022, https://www.scientificamerican.com/article/we-need-to-improve-indoor-air-quality-here-rsquo-s-how-and-why/.
  39. Ueki H, Ujie M, Komori Y, Kato T, Imai M, Kawaoka Y. Effectiveness of HEPA Filters at Removing Infectious SARS-CoV-2 from the Air. mSphere. 2022 Aug 31;7(4):e0008622. doi: 10.1128/msphere.00086-22. Epub 2022 Aug 10. PMID: 35947419; PMCID: PMC9429918. https://pubmed.ncbi.nlm.nih.gov/35947419/.
  40. Johansson MA, Quandelacy TM, Kada S, et al. SARS-CoV-2 Transmission From People Without COVID-19 Symptoms. JAMA Netw Open. 2021;4(1):e2035057.  https://doi.org/10.1001/jamanetworkopen.2020.35057
  41. Delgado, Carla. “Can Rapid Covid Tests Pick up Omicron?” Verywell Health, Verywell Health, 29 Nov. 2022, https://www.verywellhealth.com/can-rapid-tests-detect-omicron-6832866.
  42. Puhach, O., Meyer, B. & Eckerle, I. SARS-CoV-2 viral load and shedding kinetics. Nat Rev Microbiol 21, 147–161 (2023). https://doi.org/10.1038/s41579-022-00822-w
  43. Clebak, K. T., Snyder, J., & Felix, T. M. (2023, April 15). Accuracy of Point-of-Care rapid antigen tests for diagnosis of COVID-19. AAFP. https://www.aafp.org/pubs/afp/issues/2023/0400/cochrane-poc-rapid-antigen-tests-for-diagnosis-of-covid-19.html
  44. Adam, David. “How Long Is Covid Infectious? What Scientists Know so Far.” Nature News, Nature Publishing Group, 26 July 2022, https://www.nature.com/articles/d41586-022-02026-x.
  45. Paul, M. (2023, September 11). COVID patients exhale up to 1,000 copies of the virus per minute during first eight days of symptoms. MedicalXpress. https://medicalxpress.com/news/2023-09-covid-patients-exhale-virus-minute.html
  46. Jaumdally, S., Tomasicchio, M., Pooran, A. et al. Frequency, kinetics and determinants of viable SARS-CoV-2 in bioaerosols from ambulatory COVID-19 patients infected with the Beta, Delta or Omicron variants. Nat Commun 15, 2003 (2024). https://doi.org/10.1038/s41467-024-45400-1
  47. Sumner MW, Xie J, Zemek R, et al. Comparison of Symptoms Associated With SARS-CoV-2 Variants Among Children in Canada. JAMA Netw Open. 2023;6(3):e232328. https://doi.org/10.1001/jamanetworkopen.2023.2328
  48. Ducharme, J. (2022, September 23). Why you should rest—a Lot—If you have COVID-19. TIME. https://time.com/6215346/covid-19-rest-helps/
  49. SARS-CoV-2 Damages Cardiomyocytes Mitochondria and Implicates Long COVID-associated Cardiovascular Manifestations. Wenliang Che, Shuai Guo, Yanqun Wang, et al. medRxiv 2024.08.18.24311961; https://doi.org/10.1101/2024.08.18.24311961