[burger]

There's a new longitudinal study of antibody levels in covid-19 patients for up to 3 months after getting the disease.  Immunity seems to drop off very quickly.  https://www.theguardian.com/world/2020/j...y-suggests

People who have recovered from Covid-19 may lose their immunity to the disease within months, according to research suggesting the virus could reinfect people year after year, like common colds.

In the first longitudinal study of its kind, scientists analysed the immune response of more than 90 patients and healthcare workers at Guy’s and St Thomas’ NHS foundation trust and found levels of antibodies that can destroy the virus peaked about three weeks after the onset of symptoms then swiftly declined.

Blood tests revealed that while 60% of people marshalled a “potent” antibody response at the height of their battle with the virus, only 17% retained the same potency three months later. Antibody levels fell as much as 23-fold over the period. In some cases, they became undetectable.

Here's the money figure:


Oh, and more bonus bad news from the same article (though it's a monkey study, so who knows):

Early results from the University of Oxford have shown that the coronavirus vaccine it is developing produces lower levels of antibodies in macaques than are seen in humans infected with the virus. While the vaccine appeared to protect the animals from serious infection, they still became infected and may have been able to pass on the virus.

This week is off to a great start :/

PS Possible silver lining from the article.

He added: “We would however expect that re-infection would be less severe for any individual as they will still retain immune memory allowing them to more rapidly respond. Nevertheless they could still be a source of onward transmission.

[burger]

There's a new longitudinal study of antibody levels in covid-19 patients for up to 3 months after getting the disease.  Immunity seems to drop off very quickly.  https://www.theguardian.com/world/2020/j...y-suggests

People who have recovered from Covid-19 may lose their immunity to the disease within months, according to research suggesting the virus could reinfect people year after year, like common colds.

In the first longitudinal study of its kind, scientists analysed the immune response of more than 90 patients and healthcare workers at Guy’s and St Thomas’ NHS foundation trust and found levels of antibodies that can destroy the virus peaked about three weeks after the onset of symptoms then swiftly declined.

Blood tests revealed that while 60% of people marshalled a “potent” antibody response at the height of their battle with the virus, only 17% retained the same potency three months later. Antibody levels fell as much as 23-fold over the period. In some cases, they became undetectable.

Here's the money figure:


Oh, and more bonus bad news from the same article (though it's a monkey study, so who knows):

Early results from the University of Oxford have shown that the coronavirus vaccine it is developing produces lower levels of antibodies in macaques than are seen in humans infected with the virus. While the vaccine appeared to protect the animals from serious infection, they still became infected and may have been able to pass on the virus.

This week is off to a great start :/

PS Possible silver lining from the article.

He added: “We would however expect that re-infection would be less severe for any individual as they will still retain immune memory allowing them to more rapidly respond. Nevertheless they could still be a source of onward transmission.

[oregontim]

Damn! But thanks for the post.

[oregontim]

Damn! But thanks for the post.

[dabigv13]

If covid doesn't kill you the first time you get it, it almost certainly will not the second time. Antibody levels are not simple measure of immunity as well, as it does not reflect cellular immunity. Still have yet to see a single proven case of a person becoming reinfected in the scientific literature.

The problem with reinfection is it makes eliminating the disease more difficult. That's why many scientists think covid19 will simply become another seasonal coronavirus eventually. But once everyone has had it, or had the vaccine for it, it will likely be another annoying cold, not a rampaging pandemic.

[dabigv13]

If covid doesn't kill you the first time you get it, it almost certainly will not the second time. Antibody levels are not simple measure of immunity as well, as it does not reflect cellular immunity. Still have yet to see a single proven case of a person becoming reinfected in the scientific literature.

The problem with reinfection is it makes eliminating the disease more difficult. That's why many scientists think covid19 will simply become another seasonal coronavirus eventually. But once everyone has had it, or had the vaccine for it, it will likely be another annoying cold, not a rampaging pandemic.

[BostonCard]

More concerning:

https://www.nature.com/articles/s41586-020-2538-8

ADE (antibody dependent enhancement), which is what happens with Dengue, is a serious concern.  This is a paradoxical scenario where having antibodies actually makes the infection worse, by enhancing entry of the virus into cells (hence "antibody dependent enhancement")

First, comprehensive studies are urgently needed to define clinical correlates of protective immunity against SARS-CoV-2. Second, since we cannot predict ADE of disease reliably after either vaccination or treatment with antibodies, regardless of what virus is the causative agent, it will be essential to depend on careful analysis of safety in humans as immune interventions for COVID-19 disease move forward.

BC

[BostonCard]

More concerning:

https://www.nature.com/articles/s41586-020-2538-8

ADE (antibody dependent enhancement), which is what happens with Dengue, is a serious concern.  This is a paradoxical scenario where having antibodies actually makes the infection worse, by enhancing entry of the virus into cells (hence "antibody dependent enhancement")

First, comprehensive studies are urgently needed to define clinical correlates of protective immunity against SARS-CoV-2. Second, since we cannot predict ADE of disease reliably after either vaccination or treatment with antibodies, regardless of what virus is the causative agent, it will be essential to depend on careful analysis of safety in humans as immune interventions for COVID-19 disease move forward.

BC

[M T]

One of the regulars on This Week in Virology (TWIV) is a clinician from Columbia Univ in NY.  On (https://www.youtube.com/watch?v=LYo9oK-Giso)this week's show he mentioned that one of his 2 patients this week (0 last week!) was a physician who was PCR-positive in March (having symptoms, and along with his family) and he treated as an outpatient.  Now, that patient is PCR-positive again but is having to be hospitalized.

He then mentioned another patient (not his) from Washington (DC or state??) that had been mentioned last week was apparently reinfected in the same time frame, again with being worse this time.  (One of those two apparently thought he was immune and dealt with a son with COVID, leading to the reinfection.)

As they said, two cases are anecdotal.

All that said, when we see that NY has so few cases now (roughly 2000/wk) after having so much COVID before (roughly 30K/wk), is it chance, is it learned behavior, or is there a biological effect?     It seems to me you don't need the percentage of (temporary) immunity to be high except in those that have wide exposure to other people.   A lot of those people were sick in March & April (even if they didn't know it).  TWIV mentioned in passing a seropositive rate of 68% for some front line people.   Kinda like a flash wildfire that burns all the dry grass won't reoccur until there is enough dry grass again.

[M T]

One of the regulars on This Week in Virology (TWIV) is a clinician from Columbia Univ in NY.  On (https://www.youtube.com/watch?v=LYo9oK-Giso)this week's show he mentioned that one of his 2 patients this week (0 last week!) was a physician who was PCR-positive in March (having symptoms, and along with his family) and he treated as an outpatient.  Now, that patient is PCR-positive again but is having to be hospitalized.

He then mentioned another patient (not his) from Washington (DC or state??) that had been mentioned last week was apparently reinfected in the same time frame, again with being worse this time.  (One of those two apparently thought he was immune and dealt with a son with COVID, leading to the reinfection.)

As they said, two cases are anecdotal.

All that said, when we see that NY has so few cases now (roughly 2000/wk) after having so much COVID before (roughly 30K/wk), is it chance, is it learned behavior, or is there a biological effect?     It seems to me you don't need the percentage of (temporary) immunity to be high except in those that have wide exposure to other people.   A lot of those people were sick in March & April (even if they didn't know it).  TWIV mentioned in passing a seropositive rate of 68% for some front line people.   Kinda like a flash wildfire that burns all the dry grass won't reoccur until there is enough dry grass again.