3 ms·

It's a good anecdote, but we have some data on this now, and from a neutralization standpoint, a prior infection is about 75-80% protective against reinfection.

It's a good anecdote, but we have some data on this now, and from a neutralization standpoint, a prior infection is about 75-80% protective against reinfection. Very good, but not quite as good as the mRNA vaccines. As for spending time in a room with the person with the high fever and coughing, it sounds like they were probably past their peak viral shedding. This usually happens the day before symptom onset or the very first day of any COVID symptoms. This is why COVID has been so difficult to contain, because by the time someone has had enough time to even notice symptoms and then go get tested, they've already shed most of the virus particles that they're going to. If they then have to wait a couple of days for a test result and don't isolate in the meantime, a positive test that late only makes a marginal difference in reducing transmission.

mulvya 5y ago
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 https://www.medrxiv.org/content/10.1101/2021.04.20.21255670v... (Pfizer vaccine) SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(2100141-3/fulltext https://www.thelancet.com/journals/eclinm/article/PIIS2589-5...
- Scoundreller 5y ago
  Be careful with your second study, because they looked at those that developed/still had antibodies post-infection. Kinda like saying those that developed a good immune response developed a good immune response. But not everyone develops long-lasting antibodies and not everyone keeps those levels high. In this study, 8-30% didn't develop/lost antibody positivity (depending on which test method used): https://wwwnc.cdc.gov/eid/article/27/3/20-4543_article https://wwwnc.cdc.gov/eid/article/27/3/20-4543_article In this study, 28% of those with documented infection had their antibodies go below the level of positivity over time: https://www.cdc.gov/mmwr/volumes/69/wr/mm6947a2.htm https://www.cdc.gov/mmwr/volumes/69/wr/mm6947a2.htm
  - mulvya 5y ago
    > Be careful with your second study, because they looked at those that developed/still had antibodies post-infection. Kinda like saying those that developed a good immune response developed a good immune response. True. It depends on which specific antibody you look for, and how. Here's a recent cohort study: Anti-SARS-CoV-2 Antibodies Persist for up to 13 Months and Reduce Risk of Reinfection https://www.medrxiv.org/content/10.1101/2021.05.07.21256823v3 https://www.medrxiv.org/content/10.1101/2021.05.07.21256823v... "Here, we longitudinally measured Spike (S) and Nucleocapsid (N)-specific antibodies in 1,309 healthcare workers (HCWs), including 916 COVID-19 negative HCWs and 393 convalescent COVID-19 for up to 422 days post-symptom. ... Overall, 69 SARS-CoV-2 infections developed in the COVID-19 negative group (incidence of 12.22 per 100 person-years) versus one in the COVID-19 positive group (incidence of 0.40 per 100 person-years), indicating a relative reduction in the incidence of SARS-CoV-2 reinfection of 96.7% (p<0.0001)." Of course, these antibodies <--> protection studies are a bit of streetlamp effect phenomenon. Antibodies are relatively easy to measure so that's what immune endurance studies tend to check for. The relative risk of reinfection in real-world settings is the more robust measure.

mulvya 5y ago

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 https://www.medrxiv.org/content/10.1101/2021.04.20.21255670v... (Pfizer vaccine) SARS-CoV-2 antibody-positivity protects against reinfection for at least seven months with 95% efficacy https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(2100141-3/fulltext https://www.thelancet.com/journals/eclinm/article/PIIS2589-5...

Scoundreller 5y ago
Be careful with your second study, because they looked at those that developed/still had antibodies post-infection. Kinda like saying those that developed a good immune response developed a good immune response. But not everyone develops long-lasting antibodies and not everyone keeps those levels high. In this study, 8-30% didn't develop/lost antibody positivity (depending on which test method used): https://wwwnc.cdc.gov/eid/article/27/3/20-4543_article https://wwwnc.cdc.gov/eid/article/27/3/20-4543_article In this study, 28% of those with documented infection had their antibodies go below the level of positivity over time: https://www.cdc.gov/mmwr/volumes/69/wr/mm6947a2.htm https://www.cdc.gov/mmwr/volumes/69/wr/mm6947a2.htm
- mulvya 5y ago
  > Be careful with your second study, because they looked at those that developed/still had antibodies post-infection. Kinda like saying those that developed a good immune response developed a good immune response. True. It depends on which specific antibody you look for, and how. Here's a recent cohort study: Anti-SARS-CoV-2 Antibodies Persist for up to 13 Months and Reduce Risk of Reinfection https://www.medrxiv.org/content/10.1101/2021.05.07.21256823v3 https://www.medrxiv.org/content/10.1101/2021.05.07.21256823v... "Here, we longitudinally measured Spike (S) and Nucleocapsid (N)-specific antibodies in 1,309 healthcare workers (HCWs), including 916 COVID-19 negative HCWs and 393 convalescent COVID-19 for up to 422 days post-symptom. ... Overall, 69 SARS-CoV-2 infections developed in the COVID-19 negative group (incidence of 12.22 per 100 person-years) versus one in the COVID-19 positive group (incidence of 0.40 per 100 person-years), indicating a relative reduction in the incidence of SARS-CoV-2 reinfection of 96.7% (p<0.0001)." Of course, these antibodies <--> protection studies are a bit of streetlamp effect phenomenon. Antibodies are relatively easy to measure so that's what immune endurance studies tend to check for. The relative risk of reinfection in real-world settings is the more robust measure.