Covid19 not as easy to transfer as currently thought?

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Covid19 not as easy to transfer as currently thought? - magnus - 04-09-2020

There's a German group of scientists doing a study in one of the German hotspots. Thus far mainly interviews and swabs.

One of the early observations is that transfer from objects would be really hard as the virus seems to dry out fast.

There's also some stuff on serology and IFR or CFR.
[Tweet]https://twitter.com/NAChristakis/status/1248228331352461312?s=20[/tweet]

Hope there's truth in this.

RE: Covid19 not as easy to transfer as currently thought? - BostonCard - 04-09-2020

A much higher prior infection rate (and consequently a lower IFR) would be brobdingnagian.

BC

RE: Covid19 not as easy to transfer as currently thought? - dabigv13 - 04-09-2020

I've been hoping this thing was more infectious than we realize (meaning higher prevalence than known, and thus lower fatality rate). I think that's the case and the fatality rate will end up between 0.5 and 1% and hopefully closer to 0.5.

It also makes sense that fomite transmission is uncommon. Covid is a respiratory virus. We've been talking about hand washing and disinfecting packages and such, but that's just because it's one of the only things individuals can control, so giving them some agency to fight this is good for that psychological reason alone. But the widespread adoption of masking will be much more important in reducing transmission.

RE: Covid19 not as easy to transfer as currently thought? - BostonCard - 04-09-2020

Masking still has to be done in conjunction with other measures (hand washing and decreased person-to-person contact). While I agree that transmission via fomites is probably uncommon, transmission by passing the virus directly on hands (infected person coughs into hand, shakes hands with healthy person, healthy person hand scratches an itch under their nose) is probably pretty high. And with masks, it is natural for people not used to them to frequently adjust them due to discomfort. That's why hand washing and reducing hand-to-hand contact makes sense.

As an aside, I skimmed the article linked in the tweet and didn't see the numbers they reported. Did I miss them?

BC

RE: Covid19 not as easy to transfer as currently thought? - burger - 04-09-2020

I've seen at least 3 or 4 models that predict fairly high R0 values (like >4), including the one from Imperial College and one that was in PNAS this week, I think. Those R values lead to the prediction of a high number of infected people, most of which would have to be asymptomatic or have mild symptoms to match up with observed numbers of hospitalizations and deaths.

I've been dismissive of those models as wishful thinking, but we won't really know until the antibody surveillance comes in.

Do these antibody test numbers account for false positives and negatives? If you know the sensitivity and specificity of a test, it should be trivial to correct for both, right?

RE: Covid19 not as easy to transfer as currently thought? - dabigv13 - 04-09-2020

Yeah, 14% prevalence would be really high but I don't see those numbers in the article. And yes handwashing definitely important in conjunction with masking. But people being anal about their groceries and takeout packaging and such, probably overkill, but no harm in it.

RE: Covid19 not as easy to transfer as currently thought? - stupac2 - 04-09-2020

(04-09-2020, 11:00 AM)dabigv13 Wrote: Yeah, 14% prevalence would be really high but I don't see those numbers in the article. And yes handwashing definitely important in conjunction with masking. But people being anal about their groceries and takeout packaging and such, probably overkill, but no harm in it.

There's some harm if it makes people anxious and fearful about things that are actually quite safe. I wouldn't be surprised if things that involve that sort of transfer like getting restaurant food to go have taken a hit because people worry about how to sanitize it.

RE: Covid19 not as easy to transfer as currently thought? - BostonCard - 04-09-2020

(04-09-2020, 11:00 AM)burger Wrote: I've seen at least 3 or 4 models that predict fairly high R0 values (like >4), including the one from Imperial College and one that was in PNAS this week, I think. Those R values lead to the prediction of a high number of infected people, most of which would have to be asymptomatic or have mild symptoms to match up with observed numbers of hospitalizations and deaths.

I've been dismissive of those models as wishful thinking, but we won't really know until the antibody surveillance comes in.

Do these antibody test numbers account for false positives and negatives? If you know the sensitivity and specificity of a test, it should be trivial to correct for both, right?

You can calibrate the specificity by looking at pre-2020 banked plasma. The prevalence of antibodies should be zero back then. Sensitivity can be established by testing known Covid-19 (with positive PCR tests) after convalescence. And yes, then it should be possible to adjust.

BC

RE: Covid19 not as easy to transfer as currently thought? - dabigv13 - 04-09-2020

This study estimates Ro of 5.7. If so, suggests wider prevalence and thus lower fatality rate.

https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article

RE: Covid19 not as easy to transfer as currently thought? - magnus - 04-09-2020

(04-09-2020, 10:55 AM)BostonCard Wrote: As an aside, I skimmed the article linked in the tweet and didn't see the numbers they reported. Did I miss them?

There's a link in a followup tweet pointing to a release from the study...but it's in German and appears to have been taken down.

Also, a new followup shows another article based on the study.

RE: Covid19 not as easy to transfer as currently thought? - Genuine Realist - 04-09-2020

(04-09-2020, 02:36 PM)magnus Wrote:
(04-09-2020, 10:55 AM)BostonCard Wrote: As an aside, I skimmed the article linked in the tweet and didn't see the numbers they reported. Did I miss them?

There's a link in a followup tweet pointing to a release from the study...but it's in German and appears to have been taken down.

Also, a new followup shows another article based on the study.

What was the R0 for SARS? If anyone knows?

RE: Covid19 not as easy to transfer as currently thought? - dabigv13 - 04-09-2020

Wikipedia's says between 2 and 4. But Ro is variable. SARS was able to be pushed down below 1 very easily once it was recognized because typically only very symptomatic patients were passing it on. Coronavirus requires stronger distancing measures to lower Ro because of the degree of mild or asymptomatic cases which are still transmissible.

It seems we may have reduced it to 1 or even below 1 at least in California at this time.

RE: Covid19 not as easy to transfer as currently thought? - BostonCard - 04-09-2020

(04-09-2020, 07:17 PM)dabigv13 Wrote: Wikipedia's says between 2 and 4. But Ro is variable. SARS was able to be pushed down below 1 very easily once it was recognized because typically only very symptomatic patients were passing it on. Coronavirus requires stronger distancing measures to lower Ro because of the degree of mild or asymptomatic cases which are still transmissible.

It seems we may have reduced it to 1 or even below 1 at least in California at this time.

Exactly. Paradoxically, what makes SARS-COVID-2 so dangerous is that it does not cause universally severe disease. The advantage that public health officials had in fighting SARS, MERS, and Ebola is that it was easy to identify who was sick and who was contagious. Fighting Covid-19 is like being in a sea of icebergs. For each case you see at the surface, there are several under the water that you can't see.

BC

RE: Covid19 not as easy to transfer as currently thought? - Goose - 04-09-2020

(04-09-2020, 07:45 PM)BostonCard Wrote: Exactly. Paradoxically, what makes SARS-COVID-2 so dangerous is that it does not cause universally severe disease. The advantage that public health officials had in fighting SARS, MERS, and Ebola is that it was easy to identify who was sick and who was contagious. Fighting Covid-19 is like being in a sea of icebergs. For each case you see at the surface, there are several under the water that you can't see.

BC

Amen! These cases may not show symptoms for 2-3 days while they are spreading the disease. If the subject doesn't get real sick, they may not notice and spread the disease for weeks.

RE: Covid19 not as easy to transfer as currently thought? - baymeadows3408 - 04-10-2020

(04-09-2020, 09:28 PM)Goose Wrote:
(04-09-2020, 07:45 PM)BostonCard Wrote: Exactly. Paradoxically, what makes SARS-COVID-2 so dangerous is that it does not cause universally severe disease. The advantage that public health officials had in fighting SARS, MERS, and Ebola is that it was easy to identify who was sick and who was contagious. Fighting Covid-19 is like being in a sea of icebergs. For each case you see at the surface, there are several under the water that you can't see.

BC
Amen! These cases may not show symptoms for 2-3 days while they are spreading the disease. If the subject doesn't get real sick, they may not notice and spread the disease for weeks.

I'm in grad school right now so I can become a speech-language pathologist, and I have concerns about how my future job might put me in danger. SLPs tend to work in hospitals (close contact with sick people for things like swallowing evaluations), schools (known breeding grounds for disease), and in speech clinics (kids and adults coming in and out all day and having kids touch materials). The clinician and the client need to be able to see each other's faces for things like articulation therapy. I've had kids cough directly onto me. I'm not going to be comfortable doing this kind of work until A) there's a vaccine B) there is rapid testing to prove that the person I'm working with is not an asymptomatic carrier C) there is a treatment that makes COVID-19 less heinous if you do contract it or D) we have overall herd immunity, but it looks like I may not be comfortable for a while.

RE: Covid19 not as easy to transfer as currently thought? - magnus - 04-12-2020

Well, this news bit is the opposite of this thread topic.

https://www.wcnc.com/mobile/article/news/health/coronavirus/charlotte-woman-hasnt-left-her-house-in-three-weeks-but-tested-positive-for-covid-19/275-77707b1d-fd2f-4a36-bf3e-16beca4104c4

A woman who hasn't left her house in 3 weeks tested positive for coronavirus. She does live with her husband (though separate room) and had groceries delivered once (apparently delivery person later tested positive). Source of transmission unclear.

RE: Covid19 not as easy to transfer as currently thought? - Snorlax94 - 04-12-2020

Well, this is scary, but the article does say
“the only other person she’s come into contact with is a woman who volunteered to drop off groceries at her doorstep once. Brummert said the woman later tested positive for COVID-19.

“I barely had any contact,” she said. “I didn’t even touch her.”

It sounds like she talked with the person who dropped off groceries, who later tested positive. So respiratory droplets still sounds very possible .

I’ve noticed Costco and Target, just in the last couple weeks, have installed clear plastic walls to protect the cashiers. Struck me as a good idea.

RE: Covid19 not as easy to transfer as currently thought? - M T - 04-12-2020

(04-12-2020, 03:33 AM)Snorlax94 Wrote: Well, this is scary, but the article does say
“the only other person she’s come into contact with is a woman who volunteered to drop off groceries at her doorstep once. Brummert said the woman later tested positive for COVID-19.

“I barely had any contact,” she said. “I didn’t even touch her.”

It sounds like she talked with the person who dropped off groceries, who later tested positive. So respiratory droplets still sounds very possible .

The video said "She said hello from a distance". Fomites on the grocery bags or groceries or the packages she picked up seem as likely as "from a distance".

RE: Covid19 not as easy to transfer as currently thought? - oldalum - 04-12-2020

(04-12-2020, 12:06 PM)M T Wrote: Fomites on the grocery bags or groceries or the packages she picked up seem as likely as "from a distance".

yes, it seems more likely to me: infectious person carries bags by their handles up to the front door; minutes later, the woman picks the bags up by the handles with bare hands, no indication that she washed her hands immediately after this. She didn't have to touch her directly. (the alternative is scarier, that the deliverer produced an aerosol above the bags that lingered and the woman breathed in when she picked them up.) The irony is that she wore gloves to bring in the mail every few days, which I think is a much lower risk type of exposure.

Whenever I come into the house after a trip or handling dropped-off packages, the first thing I do is hand wash. It's very hard to keep all surfaces uncontaminated, but the hands are the key end transmitter.

RE: Covid19 not as easy to transfer as currently thought? - M T - 04-12-2020

(04-12-2020, 01:35 PM)oldalum Wrote: The irony is that she wore gloves to bring in the mail every few days, which I think is a much lower risk type of exposure.

Why lower? The postman that put the mail in her mailbox (or the one that sorted her mail an hour earlier) is somehow less likely to get COVID-19 than the woman that brought the groceries?

We don't know if the woman who was working hard to stay safe was taking precautions from the groceries themselves (vegetables, food containers (esp. cold/frozen)). Nor do we know if she could have been exposed via a pet.

I am someone who hopes he is being overly cautious. You do what you can, but sometimes you make mistakes. For some of us, those few mistakes might cost our life so we avoid them. When you do make mistakes, you hope that others have done what they could to protect you, and you hope that happenstance works in your favor.

I really hope this lady is fortunate enough that she pulls through this without too much damage.