Although herd immunity still is an approach to overcome the coronavirus pandemic; is there ivedence that this approach provides long term immunity?
This is a good article to read. From LiveScience.
"Can antibody tests tell if you're immune to COVID-19?"
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Here is a part of the article:
Does having antibodies mean I'm immune?
Another tricky part of antibody testing is that we don't know what it means for long-lasting or even short-term immunity. Some people who have beaten COVID-19 may not generate antibodies at all, but that may not mean they're not immune. For instance, a study published April 6 to the preprint database medRxiv, found that of 175 COVID-19 patients in China, about 30% (who tended to be younger) had very low levels of antibodies — yet those people also recovered just fine. And it's also possible that the body makes different antibodies than a test will pick up, meaning you could be immune but still test negative. On the flip side, some people may develop antibodies, but those antibodies may not be very effective at neutralizing the virus, Ott said.
https://www.livescience.com/coronavirus-antibody-tests.html?utm_source=Selligent&utm_medium=email&utm_campaign=17355&utm_content=20200430_Coronavirus_Infographic+&utm_term=4453673&m_i=rEIqlRS4FAIiacjbq_WuIxAy2GDB2hn93dLa9YcFV32Bwr0S568%2B4Gc4t%2BouGTU%2B_u3ZLlXJH7Zh%2BcdBIqbaPeq%2BcrkjK6
Some people may develop antibodies against coronavirus, but the titer of Ab may differ from person to person. If patients don't have any other chronic diseases and his immunity will stronger and that patients must have higher serum Ab titre.
Herd immunity is an absurd approach to coronavirus. Unless you want 10 or 15% of your population dead.
Herd immunity has 2 kinds: (1) let it happens naturally (like Sweden is doing now), and (2) vaccinate the population. Immunity through vaccination makes more sense.
"Sweden records deadliest week of century after resisting lockdowns" (4/28/2020)
Sweden recorded its deadliest week of the 21st century after controversially resisting coronavirus lockdown measures, according to a report.
At least 2,505 Swedes died between April 6 and April 12, amounting to 358 fatalities per day, Swedish outlet The Local reported.
https://nypost.com/2020/04/28/sweden-records-deadliest-week-of-century-after-resisting-lockdowns/
I guess there are few data, if any, regarding specifically covid-19.
However, to coronavirus in general, read: "Time course of the immune response to experimental coronavirus infection of man". Epidemiology and Infectology, 1990.
In this experiment, the authors infected 15 volonteers with coronavirus. Some of them developed cold-like symptoms, some other not. All of them had some antibodies against coronavirus, whose titers enhanced significantly after this controlled infection.
One year later, one of the volonteers did not return as he had had stronger symptoms. In most of them, the antibodies´titers had declined. But then a second infection did not provoke symptoms, but some of the volonteers shed virus, but for a short period of up two days.
Probably, the same principles apply to this new strain of coronavirus - covid19
Interesting answer by Dario. However Covid 19 seems to be somewhat different from other coronaviruses
Price a population has to pay for developing herd immunity against COVID-19
United Kingdom did not bother to react by enforcing social distancing and lockdowns in the early part of the COVID-19 pandemic and till is now paying a heavy price because of their miscalculation and is fast approaching to be the European country with the highest mortality.
The last part of the article below tells how one can develop herd immunity and the formula to calculate it:
A Data Science View of Herd Immunity, What do We Have to Pay to Stop The Virus?
https://towardsdatascience.com/a-data-science-view-of-herd-immunity-what-do-we-have-to-pay-to-stop-the-virus-3a05fc2ce720
Herd immunity is very difficult to define in this difficult situation. Wuhan reserch data is inconclusive on herd immunity. Amount of antibodies required to say herd immunity is at safe level is very difficult at this point of time. Yes, herd immunity will come in pictures as we can not lockdown for infinite time. Rate of death and sufficient data for analysis both parameters will be key in future....
Many recovered COVID-19 patients are reporting again with RT PCR positive; at this stage its difficult to tell about the immunity after an attack.
Fraidoon Karimi
A piece of info of how antibody lasts:
Although we still don't know how long the antibody of SARS-CoV-2 will last, we can learn some lectures from SARS-CoV, a cousin of SARS-CoV-2. Attached is a chart showing us when the antibody is produced, and how long it can protect us. Day-7, a detectable amount of antibody is observed. Antibody provides about 3~4-years of protection (in the chart, M: month, Y: year). Paper is available for download online ([1]; free access).
[1]. Duration of serum neutralizing antibodies for SARS-CoV-2: Lessons from SARS-CoV infection (2020)
Herd immunity is difficult to define in current pandemic situation.
The recovered patients also shows signs and symptom along RT-PCR positive especially the rectal swab. Which tell us about the danger face of COVID-19.
According to Dr. Shamsi (Pakistan), which strongly suggests, antibodies treatment for COVID-19 infected patients.
Herd immunity has 2 kinds: (1) let it happens naturally (like Sweden is doing now), and (2) vaccinate the population. Immunity through vaccination makes more sense.
There is a chance that when you test positive using a 'kit', the 'positive' result can also due to previous infection of other coronavirus.
The recent approved 'rapid antibody detection kit' (by FDA, US) not only can detect SARS-CoV-2 antibody, it also detected antibodies from persons who had previously infected with other coronavirus. I am on another RG discussion (1).The data was posted by @ Fuat Ozyoruk. It showed 40 positive-patients suffered only common cold, not SARS-CoV-2. See post below.
(1) The RG site:
https://www.researchgate.net/post/Are_rapid_testing_kits_safe_during_this_active_pandemic#view=5eaec8c6a2ab0856ca2e6912
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Fuat Ozyoruk's post:
Yuan-Yeu Yau, Md Rabiul Alam, Christian G Meyer, I've just heard that a rapid antibody test (18 minutes) based on Electro-chemiluminescence immunoassay has been approved by FDA. The test is able to exclude common cold coronaviruses ( HKU1, NL63, 229E, or OC43 ). Data was attached. You may find more detail in the company webpage.
https://diagnostics.roche.com/global/en/products/params/elecsys-anti-sars-cov-2.html.
< 8th April, that 26 per cent of Stockholmers will have had the virus by 1st May, > Imrose B. Muhit
For herd immunity, the population needs to reach 60-70% or even higher immunity. Now, they already have a big problem in the spread of the virus in nursing home.
Yes somehow they do have memory B- lymphocytes and IgG that can protect them
but they can get infected again with less aggressive symptoms
A lot of factors can be incorporated in this answer...
Age, immune sufficiency, genetics, pharmacogentics....
Some experts hypothized that when people are re-diagnosed with covid19 it is due to 2 main reasons ; inappropriate collection of samples or the virus was in recession.... That's why there was sort of pseudo recovery led by (false negative) results....
A lot is to be concidered regarding this virus...
Some labs have been conducting experiments on immunity and how sufficient B and T cells in the body... The retransplantation of in-vitro optimized immune cells was also one of the options of used treatments....
So, According to all immunity principles, after recovery a person should gain immunity against pathogen..... Still under invistigation in covid19
We are still waiting and hoping
Fraidoon Karimi
WHO declared that "No evidence" that recovered COVID-19 patients cannot be reinfected this past Saturday (5/3/2020).
It also said, " Most studies have shown that people who have recovered from infection have antibodies to the virus. However, some of them have very low levels of neutralizing antibodies in their blood ".
https://www.reuters.com/article/us-health-coronavirus-who/no-evidence-that-recovered-covid-19-patients-cannot-be-reinfected-who-idUSKCN2270FB
From the literature which is available till now, there is no evidence suggesting that the recovered patient have antibodies to the virus and even if its there for how much time it will last. There are reports form different parts of world suggesting there are chances of reinfection; but it may also be reactivation.
The virus is reassourted one, this mens that it posses the property of anntigenic shift and antigenic drift , for this reason no protective antibody against the next challenge.Protection may be for the same homologous strain.
From my experience the habitation of virus SARS covid 19 is defining from activity of engine reactor gases pollutions include the environment chemical activity into the river and etc . The nature of this viruses can be resolve in a few way right now . The virus can makes human feel headache , hard to breeze and finally can cause died . All of the simpton effect needs to be resolve by the medicine that could be solve all the symptoms and finally by cleaning the environment through wind and rain for my opinion .
Not known. Because of the new strain of covid 19 and no vaccine yet, there is no possibility of natural Immunity and how efficient the developed vaccine could produce antibodies.
no! they don't because there have been clearly reported cases of re-infection 100s in South korea and China.
There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection. WHO continues to review the evidence on antibody responses to SARS-CoV-2 infection.
Immunity is not certain but regarding the Coronavirus nothing is certain. We have to think in terms of probabilities and potential certification of probabilities might be planned already now: Article Certified Coronavirus Immunity as a Resource and Strategy to...
A NEW STUDY INDICATES WHY IMMUNITY TO SARS-CoV-2 NOT BE LEADING TO IMMUNITY
SARS-CoV-19 Spine Protein Mutations (particularly mutation D614G) in Europe Causing it to be more Contagious with Immunity Issues and Response to any Vaccine.
The Conclusion of the study reads:
“The mutation Spike D614G is of urgent concern; it began spreading in Europe in early February, and when introduced to new regions it rapidly becomes the dominant form. Also, we present evidence of recombination between locally circulating strains, indicative of multiple strain infections. These finding have important implications for SARS-CoV-2 transmission, pathogenesis and immune interventions.”
https://www.biorxiv.org/content/10.1101/2020.04.29.069054v1
If you look at the map of corona infections, you will observe a clear preverence for the virus in Europe and the Americas. Why is that? Several reasons. But I think it is also because COVID19 virus is very close to the old SARS-CoV virus. Most people in East Asia, in particular China, have already been exposed for a decade to these Coronaviruses, which simply circulate in bats. There are two genetic fingerprints that prove that we are dealing with SARS. You can read and check for the references yourself here:
Article A SARS-like Coronavirus was Expected, but nothing was done t...
It depends on the severity of the disease. From the Colombian experience, we have noticed that asymptomatic and mild cases do not develop detectable antibodies (IgG).
On the other, moderate cases have shown good titles of neutralizing antibodies.
How ever, to our knowledge, we do not have cases of SARS-CoV-2 reinfection.
It will be premature to give decision that recovered COVID-19 patients get immunity. We have to wait for more advanced testing and allow time period for few cycles to check on immunity.
Evan S Haworth
I clearly agree with you, however with little or no known property of this novel virus as regard Viral latency period to begin to think of Viral re-activation, it is safe to say, no antibodies are developed as discussed and experienced in Colombia thus opening up the possibility of no immunity.. even in cases of Some whose immune system are sensitized, the virus end up winning the battle against the antibodies.. which is why trying herding or herd immunity might be wrong against Covid-19.. so therefore from these submissions, i do not think it is incorrect to say no, no one develops immunity to the Virus.. however it could be pretty Premature as you rightly said because there are a lot of ongoing studies..
I agree with this { There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection. WHO continues to review the evidence on antibody responses to SARS-CoV-2 infection.}
There are no solid data available yet, to positively or negatively answer the question.
No visible evidences are found. so it is early to conclude regarding herd immunity
Please have a look at the following link:
https://www.researchgate.net/post/Can_people_who_recover_from_Covid-19_become_reinfected
Yes, people who have recovered from Covid-19 disease have acquired natural immunity to SARS-CoV-2 Coronavirus (causing Covid-19 disease). Blood plasma with antibodies is taken from these people and given to people who have become infected with Coronavirus and are seriously ill. It is a medical therapy currently used in some countries.
Greetings,
Dariusz Prokopowicz
Yes, the recovered patients after COVID-19 get immunity. However, the protective effect of this immunity (partial or complete) and its duration will be known when we are at least 6-12 months into the COVID-19 pandemic.
A-43. A new answer in the New York Times
Answer 43, posted on May 8, 2020.
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Study: After recovery, most people carry antibodies
The New York Times, May 7, 2020
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https://www.nytimes.com/2020/05/07/health/coronavirus-antibody-prevalence.html
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https://www.msn.com/en-us/news/health-news/after-recovery-from-the-coronavirus-most-people-carry-antibodies/ar-BB13KZiX
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I take this opportunity to inform the readers that
I have posted the following document on Research Gate:
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Notes on the pandemic of covid-19
https://www.researchgate.net/publication/340850093_Notes_on_the_pandemic_of_covid-19
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There is a list of major Web sites about the pandemic
at the end of this document.
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This document is a first draft that is currently not well written,
but it already contains a lot of useful references.
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I have a lot of important references to add to this document.
I keep improving it almost every day.
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With best regards, Jean-Claude
A-44. Complement to answer 43
Answer 44, posted on May 8, 2020.
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The New York Times gives the following reference:
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Humoral immune response and prolonged PCR positivity
in a cohort of 1343 SARS-CoV 2 patients
in the New York City region
DOI: 10.1101/2020.04.30.20085613
May 5, 2020
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https://www.medrxiv.org/content/10.1101/2020.04.30.20085613v1
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https://doi.org/10.1101/2020.04.30.20085613
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Free pdf copy:
https://www.medrxiv.org/content/10.1101/2020.04.30.20085613v1.full.pdf
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With best regards, Jean-Claude
A-45. Complement to answer 44
Answer 45, posted on May 8, 2020.
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The article says:
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“The new study relied on a test developed by Florian Krammer,
a virologist at the Icahn School of Medicine at Mount Sinai,
that has a less than 1 percent chance
of producing false-positive results.”
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With best regards, Jean-Claude
Too easrly to have definite results, but there are reports from South Corea, that people got reinfected. That questions the completeness of the antibody-reaction.
There are no real randomized prospective studies to explain this situation yet.
Please see the link below.
https://www.livescience.com/covid-19-immunity.html
Here some information i have found related on same topic--
https://www.npr.org/sections/coronavirus-live-updates/2020/04/25/844939777/no-evidence-that-recovered-covid-19-patients-are-immune-who-says
https://www.reuters.com/article/us-health-coronavirus-who/no-evidence-that-recovered-covid-19-patients-cannot-be-reinfected-who-idUSKCN2270FB
https://www.livescience.com/covid-19-immunity.html
Not all of them, many factors like exposure to toxic substances and old age can impede the immunity.
https://www.who.int/news-room/commentaries/detail/immunity-passports-in-the-context-of-covid-19
Data Probability of reinfection after recovered from COVID-19
Reinfected after recovered from COVID-19? NSAID should avoided with people with corona virus 🦠 though still lot of debates about NSAID causes weak immune but studies have shown it could suppress immune system! Well you cannot speak about survival now, because of reinfection probabilities. You need a high statistical data analysis to support that, because chances of reinfection could be low or increased exponentially due to weak immune system after COVID-19 infection.
Please have a look at the following link:
Preprint Characterization of anti-viral immunity in recovered individ...
I have not gone through any recent research yet, but previous literature of different viruses reported that immunity could get stronger to fight against reoccurrence of disease.
Preprint Multiparametric computer simulation estimating the hidden va...
More skepticism, less clarity about immunity after COVID-19
Read of this latest article on the topic:
Article COVID-19 and Postinfection Immunity: Limited Evidence, Many ...
People who have recovered from COVID 19 develop antibodies to protect from a second infection. Hopefully, SARS CoV-2 virus will induce immunity like other coronaviruses to the recovered patients. If the body develops high level of antibody to SARS-CoV-2, which is an indicator of immune protection and this will protect from reinfection. As their antibody level is high, their immune system can defend against further attack. It is thought that the virus will likely to induce a long term immunity similar to that of other coronaviruses like SARS or MERS.
It is generally accepted that the patients with compromised immunity due to comorbid situation may not be immune to this virus even they recovered but they are more prone to reinfection. if the patients have no other chronic disease then there are more chances that those patients have strong immunity against corona virus in future infection.
Please have a look.
https://www.sciencemag.org/news/2020/05/t-cells-found-covid-19-patients-bode-well-long-term-immunity’s
The immunity in recovered COVID-19 patients still needs verification. There isn´t anything confirmed until now.
f immunity is strong and long-lasting - which seems unlikely - we may never experience new epidemics of COVID-19, as with SARS, which has been missing since 2003.
If immunity lasts a few months, we would experience new epidemics each winter, although probably much less intense than the current one. This seasonality is already observed with four other human coronaviruses (HCoV-229E, HCoV-HKU1, HCoV-NL63 or HCoV-OC43), which cause all winters with colds, diarrhea and, exceptionally, pneumonia, especially in children. It is possible that the existence of cross-immunity could decrease the severity of COVID-19 in those who have already suffered infections by other coronaviruses.
In the event that community immunity is somewhat more durable, we would foreseeably face new epidemics spacedly, for example every two, five or ten years. This frequency will be influenced by whether there is group immunity that acts as a firewall for new infections. Probably more than 70% of people should have passed the infection to protect others
Fuente The Conversation Guillermo Quindós-Andrés
Catedrático de Microbiología Médica, Departamento de Inmunología, Microbiología y Parasitología, Facultad de Medicina y Enfermería, Universidad del País Vasco / Euskal Herriko Unibertsitatea
In many people, even this crippled immune response is enough to beat back the virus. But for reasons not yet fully understood, some people enter a vicious cycle. As the virus keeps replicating, the immune army that arrives to battle it starts doing its job: attacking infected cells, digesting debris and chemicals spewed out by dying cells, even killing nearby cells in an attempt to staunch the damage. Unfortunately, if the virus continues to penetrate lung cells, this army may do more damage than good. The lung tissue becomes hopelessly inflamed; the blood vessels begin to leak fluids into the lung; and the patient begins to drown on dry land. This seems to be the reason that some people become severely ill a couple of weeks after their initial infections, tenOever said.
Reference: https://www.livescience.com/covid-19-immunity.html
A study from Taiwan did show a rather low count of antibodies among those tested, the number of persons were however not large enough to be used for any statistic of estimates. But it is still a suggestion that any person infected might get the virus again.
Studies from France, Spain and Sweden only found antibodies in 1-10% of those tested. And this study from Holland show a decline in antibodies already after 6 months.
Preprint Human coronavirus reinfection dynamics: lessons for SARS-CoV-2
Further studies is needed, meanwhile I am very much on the same side of this matter as professor Björn Olsen who have labelled the idea of trying to get 'herd immunity' as completely irresponsible. At least until we have better knowledge.
As the recovered COVID 19 patients have developed high levels of antibodies to SARS-CoV-2, so they are said to have developed immunity against the virus. However, scientists say that the SARS-CoV-2 probably induces immunity like other coronaviruses but the human body might retain the memory of the virus and should be protected from reinfection.
Munira Nasiruddin Will you please link any published report or paper on that claim. This since it contradicts the paper Carol digged up where they found a surprisingly low antibody count as well as the studies I mentioned above.
With the shortcomings of the medical system in Sweden and their odd COVID-19 response. The result have a higher degree of confidence as they do no mass testing, where Sweden only test those who are suspected or certainly have had COVID-19 and the result therefore is a strong indication than people might not always develop immunity.
Please @ Dr Anders Forsgren, you can have a look at the following link https://www.livescience.com
In general, sera from virtually all healthy adults contain anti-coronavirus antibodies Pyrc et al. showed that human sera from healthy adults inhibited HCoV-NL63 infection. Additionally, they reported that IVIg can also neutralize HCoV-NL63. Immune IgG collected in Europe or the USA may be different from that collected in China as lifestyle, diet, and the environment plays an important role in the development of specific antibodies against the virus.
Irani thevarajan et al. reported that in the blood of mild-to-moderate COVID-19 hospitalized patients, the antibody-secreting cells, follicular T-helper cells, activated CD4+ and CD8+ T-cells and IgM/IgG SARS-CoV-2-binding antibodies were increased by using flow cytometry, and they found the changes persisted for at least 7 days following full resolution of symptoms.
Not sure, because SARS-CoV-2 is a new virus and very less data available on the immunity in recovered patients and reinfection.
Dear,
still, it's not confirmed. this point needs a lot of work to verification.
See this link, which is titled:
After recovering from COVID-19, are you immune?
https://www.livescience.com/covid-19-immunity.html
Who explained the following:
These people aren't reinfected, tenOever said. Their antibody levels are high and their immune system is armed against further attack. Instead, the PCR tests are simply picking up bits of inert viral genetic debris left over from the previous infection.
Fraidoon Karimi
A small study in Shanghai, which did not follow the traditional scientific peer review process, looked at blood samples from 175 patients who recovered from mild COVID-19. Nearly a third developed low levels of antibodies, and in some patients, it could not be detected at all. They also observed that elderly patients were more likely to induce higher concentrations of the antibodies than younger patients.
Munira Nasiruddin Thank you, I am only advising caution and that we need to learn if those are relapsed or reinfected cases or perhaps the tests are inaccurate before we declare an all clear for those affected by COVID-19.
Harasit Kumar Paul have read the same study that Carolyn found.
I have digged up a few stories on my own about people who apparently have been infected more than once.
Example: https://www.cbc.ca/news/canada/british-columbia/covid-19-relapse-or-reinfection-1.5546771
That page also link a story of 90 Korean cases - in a quote of that latter story these 90 cases is described as they "might be the tip of an iceberg".
Thank you for the title, but to set the record straight, I am not a Dr, neither do I have a Ph.D.
Please read this article might help :
Preprint Coronavirus drugs: Using plasma from recovered patients as a...
Till now no documented evidence of long term immunity. there are documented reports of re-infection and of plasma recovered from cured patients as therapy. So, There is immunity - but how long it lasts and how mutable is the virus- time will tell
Yes, they got immunity though we don't know how long this immunity will be sustained.
Yes, but only for this type of SARS-CoV-2 Coronavirus (causing Covid-19 disease) that they had contracted earlier. The coronavirus causing Covid-19 disease quickly mutates and creates new types of strains, so different that the body's obtained resistance to the first version of the Coronavirus may not always provide an analogous level of resistance to the next new version of the Coronavirus. General individual and collective, social immunity of the body is of great importance, because about 80 percent. people infected with SARS-CoV-2 Coronavirus do not show any symptoms or overcome this disease very mildly, just like a common cold. In such people, the immune system fights the Coronavirus itself and antibodies form in the body. On the other hand, because the SARS-CoV-2 Coronavirus is constantly mutating, so in the following years it may reappear in new varieties like flu. Society must prepare for this. In the following years, the likelihood of re-occurring pandemics similar to the one that is now is very low, because a significant proportion of citizens have already acquired natural immunity and in the following years the scale of collective, natural immunity will increase. Medical therapies used, i.e. current therapy based on blood plasma containing SARS-CoV-2 Coronavirus antibodies and a vaccine that will be created in a few months should accelerate the process of extending the scale of collective resistance of the society to this virus.
Greetings,
Dariusz Prokopowicz
I agree. eventually, the vaccine if developed, will have to be updated every year or more frequently- just like influenza vaccine
Most of researchers and doctors are doing research in this regard. Still this is not confirmed, verification will take time.
Breaking news - People do not get immunity after recovery from COVID-19.
So, we will have to live with this pandemic by preventive measures.
This is the article telling all about the latest findings:
https://www.medrxiv.org/content/10.1101/2020.06.13.20130252v1.full.pdf
Until now there is no scientific evidence regarding immunity after recovery from Covid-19. It´s necessary more time and researches to precise and confirm this aspect.
Thank you Muhammad Yousuf sir,
Could you please share the link of article here?
There is no scientific evidence yet. Besides, due to increasing reports of re-infection from various parts of the world and resurgence in populations, unfortunately, long term immunity seems unlikely.
Dear Dr. Karimi!
There is still a lot of uncertainties in relation to the length of immunity:
1) Rich, Haridy (2020). " Long-term immunity to COVID-19 questioned in new study", June 21, 2020, © 2020 New Atlas, Citation:.." A new study, published in the peer-reviewed journal Nature Medicine, has found antibody levels in subjects suffering from asymptomatic infections dropped significantly when measured two months after hospital discharge." Available at: https://newatlas.com/health-wellbeing/covid19-immunity-antibody-asymptomatic-coronavirus-resistance-duration/
2) Amanda Heidt (2020). " Studies Report Rapid Loss of COVID-19 Antibodies: The results, while preliminary, suggest that survivors of SARS-CoV-2 infection may be susceptible to reinfection within weeks or months.", 19 June 2020, NOW PART OF THE LABX MEDIA GROUP, © 1986–2020 THE SCIENTIST. Available at:
https://www.the-scientist.com/news-opinion/studies-report-rapid-loss-of-covid-19-antibodies-67650
It can be also argued that the more dynamic the virus is about to become while spreading out, the more active its genetic structure would become. In so I argue that there might already be many emerging sub-classes of this virus due to the mutation process approx. every second week. This process makes tracking down and defend against this virus difficult. Recently a new case from Hungary was reported: a 37 year-old factory director died from COVID-19 in the small town of
"Oroszlány", just after few days of being ill. Your sincerely, Bulcsu Szekely
There is no clear evidence of people who have recovered from COVID-19 to get immunity. To be immunized, it means that a person has developed an immune response against the virus and he can repulse it before getting infected again. But for SARS-CoV-2 virus, scientists have reported that it takes about three weeks to build up sufficient quantities of antibodies and even then these developed antibodies might provide protection for only a few months.
conflicting studies- some say b cell immunity (1), now one says t cell(2). some say more igG in severe disease(3) while some studies show re-infection/resurgence(4).
My experience- not all develop- why- needs to be answered- and yes a lot of practical implications of the same- herd immunity/vaccine/plasma therapy, etc
1. Liu X, Wang J, Xu X, Liao G, Chen Y, Hu CH. Patterns of IgG and IgM antibody response in COVID-19 patients. Emerg Microbes Infect. 2020;9(1):1269-1274. doi:10.1080/22221751.2020.1773324
2. Sekine T, Perez-Potti A, Rivera-Ballesteros O, et al.Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19. bioRxiv 2020.06.29.174888; doi: https://doi.org/10.1101/2020.06.29.174888
3. Bassetti M, Ansaldi F, Icardi G, et al. COVID-19: some clinical questions after the first four months [published online ahead of print, 2020 Jun 20]. Eur J Clin Invest. 2020;e13326. doi:10.1111/eci.13326
4. Smith J. South Korea reports more recovered coronavirus patients testing positive again. https://www.reuters.com/article/us-health-coronavirus-southkorea/south-korea-reports-more-recovered-coronavirus-patients-testing-positive-again-idUSKCN21V0JQ
Please also see the link below.
https://www.nature.com/articles/s41591-020-0965-6.pdf