We were at Disney before they dropped the inside mask mandate, and it was not being consistently enforced. With Delta, it looks like both parties do need to be properly masked. (We saw many people slide their masks to their chins as soon as out of sight of a CM, and not all CM were even saying anything.)
I thought I’d seen numbers somewhere. This is from the leaked CDC slide deck:
From YLE this week, on the latest research out of the UK on vaccine protection from infection (previously, the UK had been showing higher effectiveness numbers, but these are closer to what Israel has been reporting):
Yesterday, the UK (Imperial College) released results from their ongoing study called UK REACT-1. Every month this team analyzes how vaccines continue to work against the virus. The latest data is now out. From 24 June to 12 July 2021, 98,233 volunteers in the UK were tested for COVID19. Among these people, 527 tested positive; all were Delta. After asking vaccination status, vaccine effectiveness was calculated. Vaccine effectiveness was 49% for any positive (asymptomatic and symptomatic) and 59% for symptomatic disease.“
To protect against infection…
Vaccines 49% effective
The un-infected person masking +20-30% effective
The infected person masking +40-60% effective
So yeah, vaccines + proper masking. And there are going to be outliers in vaccine effectiveness, especially for those with vulnerabilities. The surgeon general is also talking about quality of masking now playing a more significant role.
I didn’t say they don’t help. In fact we have gone back to masking. I am saying the masks aren’t nearly as helpful as they were with prior variants. But apart from vaccinations, are still the best line of defense.
They calculated the 1 second, based on that article, to viral load comparisons. Delta is 1000 times higher viral load, so the math means 1 second versus 15 minutes. It is a bit of fuzzy math, but is enough to show why Delta is spreading so incredibly fast compared to previous strains.
“It lasted only a few seconds: One man walked past another man in a mall in Sydney. When officials later watched CCTV footage of the encounter, they saw that this was the only interaction between the two. But it was enough for one of the men, who didn’t realize that he was infected with the delta variant of the coronavirus, to infect the other.”
“ A recent, not-yet-peer-reviewed study suggests that the delta variant may have a viral load that is 1,000 times higher than the original virus. If that’s correct, Céline Gounder, a clinical assistant professor of medicine and infectious disease at NYU’s Grossman School of Medicine, roughly calculatedthat the equivalent amount of time for the delta variant would be one second of contact rather than 15 minutes. Still, 15 minutes was never a magic number—the CDC later revised it to say that a cumulative 15 minutes throughout the day would also be considered close contact, and it’s likely that some people were unlucky enough to catch the original virus much faster.”
So, yes, it’s possible, but it looks like this is more well-educated speculation rather than authoritative guidance yet?
One of the articles I just skimmed mentioned it was likely possible with the original variant as well, but not likely, and it doesn’t sound like they have a quantification set for Delta yet.
CDC still has 15 min in the official guidance, last updated 8/3/21.
It’s been mentioned and I think was variable between vaccinated vs unvaccinated maybe, IIRC? I don’t know if it’s made it into guidance yet or just data sets.
Since the infectious period starts sooner, I’m thinking they won’t make any changes (because the person could still have an older variant that starts later).
Skimming the guidance that was updated 7/29, the major difference is adding testing/masking for exposed vaccinated individuals:
" Quarantine if you have been in close contact (within 6 feet of someone for a cumulative total of 15 minutes or more over a 24-hour period) with someone who has COVID-19, unless you have been fully vaccinated. People who are fully vaccinated do NOT need to quarantine after contact with someone who had COVID-19 unless they have symptoms. However, fully vaccinated people should get tested 3-5 days after their exposure, even if they don’t have symptoms and wear a mask indoors in public for 14 days following exposure or until their test result is negative."
Oh, and there is more detail on this page, updated 8/3, including a caveat for schools (since I know that is an interest area for @PrincipalTinker and others) :
Close Contact through Proximity and Duration of Exposure: Someone who was within 6 feet of an infected person (laboratory-confirmed or a clinically compatible illness) for a cumulative total of 15 minutes or more over a 24-hour period (for example , three individual 5-minute exposures for a total of 15 minutes). An infected person can spread SARS-CoV-2 starting from 2 days before they have any symptoms (or, for asymptomatic patients, 2 days before the positive specimen collection date), until they meet criteria for discontinuing home isolation.
Exception: In the K–12 indoor classroom setting, the close contact definition excludes students who were within 3 to 6 feet of an infected student (laboratory-confirmed or a clinically compatible illness) if both the infected student and the exposed student(s) correctly and consistently wore well-fitting masks the entire time.
This exception does not apply to teachers, staff, or other adults in the indoor classroom setting.
In that there was some possible variability in the timeline based on vaccination status? If I run across it again, I’ll try to remember to tag you on it. But I don’t think it was significant enough to impact the guidance.
This is the last guidance from the state on schools:
The Department of Public Health recently updated its definition of a close contact to focus on close contact that occurs when indoors. As a result, the period of time that a student or staff is outside does not count as a close contact. The identification of a close contact is ONLY attributable to the time spent indoors.
Individuals will be identified as a close contact of a COVID-19 positive person if they were within 6 feet of them while indoors, for at least 15 minutes, while they were symptomatic or within the 48 hours before symptom onset. Individuals will also be identified as a close contact if they were within 6 feet for at least 15 minutes of someone while indoors, who tested positive for COVID-19 in the 48 hours before their test was taken or anytime in the 10 days after the test.
Close contacts should follow the isolation and quarantine protocols outlined by the Department of Public Health. As a reminder, close contacts who were exposed to a COVID-19 positive individual in the classroom or on the bus while both individuals were maskeddo not have to quarantine unless they were within 3 feet of distance of the COVID-19 positive individual for a total of 15 minutes during a 24-hour period. Also, individuals who are fully vaccinated or who have had confirmed COVID-19 in the last 90 days do not need to quarantine as long as they do not have symptoms
