My patient caught Covid-19 twice. So long to herd immunity hopes.

[soothsayer]

https://www.vox.com/2020/7/12/21321653/getting-covid-19-twice-reinfection-antibody-herd-immunity

Snip

“Wait. I can catch Covid twice?” my 50-year-old patient asked in disbelief. It was the beginning of July, and he had just tested positive for SARS-CoV-2, the virus that causes Covid-19, for a second time — three months after a previous infection.

While there’s still much we don’t understand about immunity to this new illness, a small but growing number of cases like his suggest the answer is “yes.”

Covid-19 may also be much worse the second time around. During his first infection, my patient experienced a mild cough and sore throat. His second infection, in contrast, was marked by a high fever, shortness of breath, and hypoxia, resulting in multiple trips to the hospital.

Recent reports and conversations with physician colleagues suggest my patient is not alone. Two patients in New Jersey, for instance, appear to have contracted Covid-19 a second time almost two months after fully recovering from their first infection. Daniel Griffin, a physician and researcher at Columbia in New York, recently described a case of presumed reinfection on the This Week in Virology podcast.

[soothsayer]

1. Also does not bode well for a vaccine

[luvtheGWN]

25. Along with other reports that the antibodies in some patients

linger for only 2 or 3 months would seem to indicate that a "useful" vaccine may be only a pipe dream.

[LisaL]

27. Yep, that's my fear as well.

Or we will have to be vaccinated multiple times per year? And I don't know of any vaccine that is administered multiple times per year.

[soothsayer]

28. I guess you could get a booster every few months

Yeah that ain’t happening

[lagomorph777]

51. That's normal. Antibodies are the immediate response; Memory B Cells are the long-term response.

Memory B cells are a B cell sub-type that are formed within germinal centers following primary infection. Memory B cells can survive for decades and repeatedly generate an accelerated and robust antibody-mediated immune response in the case of re-infection (also known as a secondary immune response).

https://en.wikipedia.org/wiki/Memory_B_cell

[luvtheGWN]

53. Thanks!

That's good to know, and must be the reason that so many scientists have high hopes for an effective vaccine.

[lagomorph777]

59. Right - we keep seeing the story about antibodies fading, as if it's a disaster.

It's just how the body works.

[Renew Deal]

63. Everyone is talking about a vaccine, but it's not really practical over the next year or so.

If one is created, can they create enough to cover 70% of the global population? Who gets it first? Is there enough material to deliver it? What are the side effects and how many people are impacted?

I think the vaccine talk before July 2022 is a fantasy.

[BannonsLiver]

2. Soothsayer? More like Doomsayer.

[soothsayer]

3. I know!

I try to make up for it with encouraging Biden tweets.

[SoonerPride]

4. This is unsurprising

And terribly depressing

[Sucha NastyWoman]

5. Another bad characteristic

It’s like this virus was specially designed to have all the worst variables possible.

[Loki Liesmith]

6. Potentially a false positive

[soothsayer]

7. But they get worse symptoms

[FBaggins]

18. There's still a difference between testing positive and being sick

More importantly... there have been millions of infections with just a handful of similar stories.

A handful of kids who get chickenpox twice does not alter the fact that, generally speaking, you’re immune once you’ve had it.

Relevant to this story... those who get it a second time generally have very minor cases the first time. Perhaps the virus didn’t take hold strongly enough to form an antibody response?

[LisaL]

33. There are some viruses that provide long lasting immunity.

And some that don't.
Right now I am thinking that evidence points to covid not providing long lasting immunity.
Studies on antibodies show that antibodies for covid don't last that long.
If covid doesn't provide long lasting immunity, vaccine could be a pipe dream.

[FBaggins]

43. At this point, we just don't know

I agree that there have been some indications that antibodies may not be long-lasting. But other indications have been better... and antibodies are not the only form of immunity. The so-called T-cell mediated immunity possibility looks stronger. And even some hint that a significant number of people may benefit from a T-cell response from a prior coronavirus (cold) infection.

I'm unwilling to get too pessimistic on the topic. With 13 million confirmed infections worldwide... I would expect to have heard of tens of thousands of such stories if reinfection were a significant thread (rather than a comparatively rare possibility).

[lagomorph777]

52. T cells and Memory B Cells are important long-term; antobodies are always short-term protection.

Most people really have no clue how the immune system works so this kind of story gets sensationalized.

[Drahthaardogs]

48. Almost impossible

PCR is the only test used to denote an active infection. False negatives are common. False positives really do not happens unless cross contamination occurred

[smirkymonkey]

65. I think so.

[Docreed2003]

8. We've had patients that tested positive in March and April

Who had procedures postponed due to the pandemic, show persistent positive tests in the pre-surgery evaluations. They're completely asymptomatic and unlikely to be shedding the virus. These aren't new cases, just persistent positive tests. This phenomena has been seen all over the world.

Edit to add: Some patients will have significant and potentially worsening symptoms weeks to months after their initial infection.

[AkFemDem]

9. Yes this!! This article is describing a well documented phenomenon

The patient did not have the virus twice, they just never fully shed it.

This does not mean we won’t eventually have a successful vaccine and herd immunity.

[soothsayer]

11. So people don't get dengue fever multiple times either?

It’s confusing to me.

Snip
First, the trajectory of a moderate initial infection followed by a severe reinfection suggests that this novel coronavirus might share some tendencies of other viruses such as dengue fever, where you can suffer more severe illness each time you contract the disease.

[LisaL]

30. That's not the opinion of the doctor writing the article.

He believes his patient recovered fully, and then within months got infected again.
The second time around he had much worse symptoms.
There are other viruses that can do that.

[obamanut2012]

10. They did not get the virus twice

They are still shedding it.

This has been well documented all over the world.

[ecstatic]

15. Still in dispute. Unfortunately.

He addresses that idea in the article, btw.

[AllyCat]

29. A study a few weeks ago from China showed no antibody

In a group of 37 previously asymptomatic positives and a group of 37 previously symptomatic positives. Only 2-3 months after their infections, 90% had little or no antibody.

[LisaL]

31. What has been documented "all over the world" is that some people

test positive again some months after testing negative.
Some are attributing that to virus never going away in these patients.
Another possibility is that they got infected again.

[Blues Heron]

12. how do they know they caught it a second time

maybe it's just a relapse. Or are they just jumping to conclusions. How can they know the difference? Maybe genetic analysis, two different flavors of the virus? Doubt they did that though.

[soothsayer]

13. Dunno. CDC says this

Yes, they should be isolated and retested. Persons who test positive for SARS-CoV-2 by RT-PCR come out of isolation after meeting criteria for the symptom-based or test-based strategy. We do not know the degree to which previous COVID-19 illness protects against a subsequent SARS-CoV-2 infection or for how long persons are protected. Currently, serologic testing cannot be used to determine if this person may be reinfected. A positive serologic test may be evidence of the prior infection, but it remains unknown to what degree persons with detectable anti-SARS-CoV-2 antibodies are immune to reinfection. Contact tracing for the second period of symptoms (new case investigation) may be warranted.

And this

The person should be managed as potentially infectious and isolated. When a positive test occurs less than about 6 weeks after the person met criteria for discontinuation of isolation, it can be difficult to determine if the positive test represents a new infection or a persistently positive test associated with the previous infection. If the positive test occurs more than 6-8 weeks after the person has completed their most recent isolation, clinicians and public health authorities should consider the possibility of reinfection. Ultimately, the determination of whether a patient with a subsequently positive test is contagious to others should be made on a case-by-case basis, in consultation with infectious diseases specialists and public health authorities, after review of available information (e.g., medical history, time from initial positive test, RT-PCR Ct values, and presence of COVID-19 signs or symptoms). Persons who are determined to be potentially infectious should undergo evaluation and remain isolated until they again meet criteria for discontinuation of isolation or of transmission-based precautions, depending on their circumstances.

[Blues Heron]

20. Cool, good info, thanks Soothsayer

[Orangepeel]

17. making that argument is the reason for the article

"It is possible, but unlikely, that my patient had a single infection that lasted three months. Some Covid-19 patients (now dubbed “long haulers”) do appear to suffer persistent infections and symptoms.

My patient, however, cleared his infection — he had two negative PCR tests after his first infection — and felt healthy for nearly six weeks.
I believe it is far more likely that my patient fully recovered from his first infection, then caught Covid-19 a second time after being exposed to a young adult family member with the virus. He was unable to get an antibody test after his first infection, so we do not know whether his immune system mounted an effective antibody response or not.

Regardless, the limited research so far on recovered Covid-19 patients shows that not all patients develop antibodies after infection. Some patients, and particularly those who never develop symptoms, mount an antibody response immediately after infection only to have it wane quickly afterward — an issue of increasing scientific concern."

[Blues Heron]

19. Thanks! guess I should have read the article!

[LisaL]

26. Even the ones who develop antibodies don't seem to keep them that long.

From weeks to months.

[ecstatic]

14. We are so screwed

Dump pinned all his hopes on summer and herd immunity.

Now what??

[LisaL]

24. Summer already didn't work.

Covid is spreading very well in the summer.

[SpaceNeedle]

16. One cannot catch Covid twice. The problem is with the PCR.

THE PCR test detects viral RNA -- which lingers in nasal sinuses for weeks. The second positive test detected the viral RNA - so the test was positive but the virus was dead.

[Blues Heron]

21. except he was very sick the second time around

He didn't just test positive, he got sick twice.

" His second infection, in contrast, was marked by a high fever, shortness of breath, and hypoxia, resulting in multiple trips to the hospital."

[soothsayer]

22. Dunno, seems the jury is out as yet, but I hope you're right

[LisaL]

23. Not true at all.

We don't know that "one can't catch covid twice." There is no limit on how many times one can catch flu or cold. The same could very well be true for covid.
Antibody levels go down quickly. That could suggest short lived immunity.

[soothsayer]

34. And the dengue fever cautionary tale is a good one

[PoindexterOglethorpe]

58. There are many, many different viruses that cause colds and flu.

Generally speaking, each cold or flu you have comes from a different virus. There is some evidence that some of the corona viruses which cause colds can re-infect a person some time after they've gotten and recovered from the previous that-corona-virus-caused-cold.

Rhinoviruses are the main source of colds. Once you recover from one of those, you won't get sick the next time you come up against that specific rhino virus.

Flu viruses are more complicated, but at least some immunity is conferred if you get an then recover from a specific flu virus.

[Chemisse]

36. That is the issue with people who continue to test positive but are asymptomatic.

But that is not the situation here.

[SoonerPride]

37. Welcome to DU!

And sadly you are wrong.

People can catch the coronavirus twice.

[Chemisse]

32. This is not totally surprising considering recent studies about antibodies.

Here is one article about a study from last month:

You May Have Antibodies After Coronavirus Infection. But Not for Long.

https://www.nytimes.com/2020/06/18/health/coronavirus-antibodies.html article, which refers to this study: https://www.nature.com/articles/s41591-020-0965-6

Antibodies — protective proteins made in response to an infection — may last only two to three months, especially in people who never showed symptoms while they were infected.

The conclusion does not necessarily mean that these people can be infected a second time, several experts cautioned. Even low levels of powerful neutralizing antibodies may still be protective, as are the immune system’s T cells and B cells. But the results offer a strong note of caution against the idea of “immunity certificates” for people who have recovered from the illness, the authors suggested.

Antibodies to other coronaviruses, including those that cause SARS and MERS, are thought to last about a year. Scientists had hoped that antibodies to the new virus might last at least as long.

“These reports highlight the need to develop strong vaccines, because immunity that develops naturally during infection is suboptimal and short-lived in most people.”

[soothsayer]

35. Strong vaccines sound worrisome because that really bad immune response is deadly

[SoonerPride]

38. We may end up with a vaccine you get monthly.

And then perhaps an oral instead of injected solution.

If I could invent that I'd be a billionaire!

[soothsayer]

42. First ones will likely be intravenous

I like the pill idea better

[BSdetect]

39. This is extremely serious.

[Proud Liberal Dem]

40. Continued study of this is necessary

but it seems to be only a small number of cases where this is being reported but the implications are not yet clear. If it were happening in a larger number of cases relative the total amount of cases to date, I'd be more worried but so far we are only hearing about a few.

[soothsayer]

41. Early days

[Proud Liberal Dem]

45. Yes

but not as early as before. We're somewhere between 7 (or more depending on when it actually emerged) months and it's spread worldwide now. The situation in China would be our most accurate read on the situation and, at least so far, there's not large numbers of Chinese persons whom have been re-infected (that we know about). I agree that more time and study is going to be needed but given how widespread and communicable the disease is, it seems like if re-infection was a serious problem, we should be hearing about it happening to more people?

[soothsayer]

46. I'll vote for that reality

Don’t like the sound of reinfection

[BGBD]

44. immunity from an infection.....

and a vaccine are not the same thing. There are ways to boost the immune response during a vaccination to provide better protection.

Secondly, cases where someone is actually testing positive and getting sick again arr corner cases. They are rare, which is expected even with diseases that we know provide immunity like mono. There are people who have it twice, but that doesn't mean that everyone who catches it can get it again.

Sometimes immune systems don't respond as they should and other times a virus infects despite an immune response.

[UTUSN]

47. Oh good grief.

[Baclava]

49. Got sick and then infected again 2 months later? Is it possible it was from a new mutated strain?

In which case a vaccine will never work because the virus is constantly mutating like the rhinovirus of the common cold with hundreds of strains

[lagomorph777]

50. There will always be some people with poor immune response. Too soon to say everybody is like that.

Herd immunity is a statistical thing. If 60% - 70% of us can develop not only the antibodies (the ammo) but the long-term memory of how to manufacture the antibodies (ammo factory), we can eventually beat this.

[SoonerPride]

54. There is no coronavirus vaccine of any type

The antibodies typically don't last more than a few months.

The usual coronavirus that people catch is referred to as the common cold, and there is no vaccine because they wouldn't work.

Don't expect one in this novel coronavirus case either.

[lagomorph777]

60. The problem with the cold is that it's many different viruses; some of them are coronaviruses.

And all of them mutate frequently. We can be immune to each of them but then there's always another mutation.

[BGBD]

55. absolutely

We have had millions of confirmed cases in the US, and only a small percentage of those have tested positive again and only a handful of those have gotten sick again.

If 99.5% of patients aren't being reinfected, I'm not sure we can focus o n the 0.5% who have and say that means immunity isn't happening and a vaccine won't work.

[Quixote1818]

61. Correct, the T cells seem to be gaining memory of Covid 19

even if the antibodies are no longer present. Most experts believe most people will have some level of immunity for a year or longer.

[kcr]

56. One doctor thinks it happened with one of their patients

That is not a study. The headline is click-bait, which is typical of Vox.

[SoonerPride]

57. The headline didn't say it was a study.

What are you talking about?

[kcr]

62. So? I didn't say the headline said that.

I said the headline is clickbait and gave the reasons I think so.

[Celerity]

67. indeed, here is an article that deals with it, and other gloom and doom hype

https://www.democraticunderground.com/100213783118

[roamer65]

64. Our best hope right now is monoclonal antibody therapy.

If a effective vaccine cannot be developed, dosing infected people with neutralizing antibodies is the best line of defense.

[Celerity]

66. this is a hyped-up FUD article, and is dealt with here

https://www.democraticunderground.com/100213783118