Actually, several preprints here in researchgate are showing that not all the population is susceptible to covid-19. There seems to be a high proportion of immune crossed response to the other coronaviruses, that is, about at least 50-60% of the population present T-lymphocytes that react against covid, even though they have not had a covid infection. Anyway, I guess that day after day no more covid deaths will be recorded, as those more susceptible persons will have already had contact with covid, and it will be the fifht human coronavirus circulating along the world. Anyway, the former mysterious infantile syndrome of Kawasaki was now cleared: it is due to a immunopathological response against coronaviruses.

Global cases are more than 11.8 million and more than half a million died from COVID-19. Dear Dr. Dario Palhares, do you think heard immunity will work? Sweden and UK initially followed that way then switched actually.

Dear all, today in Eljazeera Chantal there was a debate in which one guest claim that today appeared a report from experts in which the theory of herd immunity is completely destroyer. The other guest replies simply : if this is true, there is no need to look for a vaccin since it will be useless. A very Logic reply.

Personaly this theory still persist and there is no alternatives to herd immunity. My Regards

Two things actually, herd immunity with vaccination and without vaccination: the second one failed actually according to study, dear Abdelkader BOUAZIZ and hope mass coverage with suitable vaccine it can be possible but without it it the theory will be just disaster. UK faced the problem initially.

I think till now, few is known about the influence of the international policy on the information about the real impact of this pandemic, it is like that the mass media is trying to orient our way of thinking. Much more will be elucidated in the coming future.

Without vaccination the hope of controlling Corona by spreading only will be just a disaster as it's very fatal diseases, dear Abdelkader BOUAZIZ and we have examples of control of polio, measles, rabies, tetanus by vaccination too.

I think that

Thanks for your concern dear Terri Purvis

Dear Dr. Alam!

You spotted a major point! Based on the available evidence one cannot trust herd immunity protection against COVID-19:

1) Lucy, C. Okell, et al. (2020)." Have deaths from COVID-19 in Europe plateaued due to herd immunity?" THE LACENT Vol. 395, Issue 10241, June 2020 © 2020 Elsevier Ltd., Available at:

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31357-X/fulltext

2) Laura Gallagher (2020). "Declines in COVID-19 cases not due to herd immunity, says analysis" 12 Jubn 2020, Article text (excluding photos or graphics) © Imperial College London. Available at: https://www.imperial.ac.uk/news/198238/declines-covid-19-cases-herd-immunity-says/

3) Ewen Callaway, Heidi Ledford & Smriti Mallapaty (2020). "Six months of coronavirus: the mysteries scientists are still racing to solve - From immunity to the role of genetics, Nature looks at five pressing questions about COVID-19 that researchers are tackling." 03 July 2020, Nature 583, 178-179 (2020) Citation: "What’s the nature of immunity and how long does it last?...." , © 2020 Springer Nature Limited, Available at:

https://www.nature.com/articles/d41586-020-01989-z

It has been confirmed that this virus easily mutates, but it is not known how it would affect immunity: "A spate of studies have suggested that this mutation makes the SARS-CoV-2 virus more infectious to cultured cells, but it is not clear how this property translates to infections in humans." Reference: Ewen Callaway, Heidi Ledford & Smriti Mallapaty (2020). "Six months of coronavirus: the mysteries scientists are still racing to solve ...please see the link 3) above.

Still sooner or later a major mutation may well lead to new symptoms of and need for novel treatment against COVID-19. One can conclude that aiming at reaching appropriate herd immunity level might not be an efficient method to fight COVID-19. Your sincerely, Bulcsu Szekely

Thanks for nice sharing and I do agree dear Bulcsu Szekely

Synergestic effects of Individual Immunity - https://www.thehindu.com/thread/science-health-environment/is-herd-immunity-even-a-viable-strategy-for-covid-19/article31796011.ece

Thanks for sharing dear Jaydip Datta

Herd immunity is not a good idea for COVID-19. There is such a propensity for complications from any infection with it, even asymptomatic infections, with multiple organ damage, scarring, oncogenesis. These complications should not happen with a good vaccine. We shouldn't take the risk in supporting herd immunity. (My personal opinion) Thank you and stay safe.

Think so sir Gary Joseph Ordog and It's roaring again. We have to find out the way to control.

PPE until a good vaccine is given.

It's quite impossible to supply 3 to 4 billion PPEs regularly for an unlimited time dear Gary Joseph Ordog . Just social distancing with healthy behavior and compulsory use of face mask in gathering or outside of home will be fine to control the spread.

With organized production, for example, one small percent of one Health organization's budget could cover this very easily. The money would surely be saved in health care expenditure. A single wealthy benefactor could easily cover this as well. This is a small expense, compared to say, the pharmaceutics used to treat the results. Thank you

Price is not question here, actually PPE is only for front line workers and it's not needed for all. Sorry dear Gary Joseph Ordog , as a physician I know too how costly the PPE is! Even you can not find N95 face mask everywhere. According to health guidelines, we need to practice healthy behavior with using face mask in gathering and maintain social distancing. Again, PPE is not advised for all and no need to use it.

I appreciate and respect your opinion, and the freedom for us to be able to express them. ( I think price is part of the question, especially now the the supply problem is being rectified. I disagree that PPE is only for front line workers. You mention that we should all use face masks, that I consider PPE. At least here, and now, N-95 are readily available and being manufactured in massive quantities. I think you are going by old WHO guidelines, at a time when there was a severe shortage of PPE, at least here, this has been remedied. I disagree that PPE is not needed for all. All people should have access to personal protection, otherwise that portion of the population is being "written off."

There is a reason to use it (PPE or protection), as more information becomes available. A sneeze is now up to 27 feet, the virus is now considered "airborne," fomites may contain viable virus for days, asymptomatic patients can become chronic "super shedders," etc. This is all my own personal opinion, but I thank you for the opportunity to be able to express it freely and congenially. Stay safe.

PPE is personal protective equipment that covers gown to mask everything in it. I don't want to continue further dear Dr. Gary Joseph Ordog and just want to finish here with last few lines, please think about Africa, South Asia, Latin America where food is more important than PPE and they can not afford N95 face mask for all and even surgical face mask is difficult to manage in many cases. I just tried to share the reality from third world countries. US can afford but it can not be the example for all. Even in USA we can not find people with N95 face mask always, that's why wanted to ensure behavioral change. Thanks for your nice sharing too.

Yes I think that also

Thanks for sharing dear Shno Mustafa Ali

Thanks dear Terri Purvis

If they asked, they probably would be provided. So that people can chose for themselves. Sorry I guess you missed my first post. Thank you, I shall leave, I was just trying to help.

You are so kind always and love to see your logical issues, dear Terry.

It might be true as per the data analysis of Spanish population and the World Health Organization has emphasized that we do not know if people who recover from COVID-19 are capable of getting sick again with the virus. “Individual immunity is not yet proven, much less herd immunity.

Think so dear Shivani Raval and suitable vaccination in such a condition is more difficult too when immunity is less and mutation is going on.

yes mutation is going and creating new symtoms So it is possible that a small mutation in the virus could have outsize effects in the clinical outcome of covid-19, the experts say. That has been known to happen with other viruses. But there’s no sign this is happening with the novel coronavirus.

Sorry dear Shivani Raval , I am not sure about your reply. We can see different strains in different parts of the world and getting mutated even within region-it's already reported.

I read the article and I want to discuss one point. They checked for the herd immunity (IgG) using fingerprick blood samples using the fast test (10 minutes) by the company Orient Gene Biotech COVID-19 IgG/IgM Rapid Test Cassette (Zhejiang Orient Gene Biotech, Zhejiang, China). Even thought they tested the sensitivity and specificity for this test, I really don't trust this method because it works better when using plasma samples in patients with high viral load, and not some drops of fingerprick's blood. The specificity of the test is also related to the time the symptoms started. The ideal is to collect samples from 10 or 14 days after the symptoms, but the viral load is not the same for everyone. It is higly individual and this rapid test would not work in patients with low viral loads, like for example, for the patients who had the infection but kept assymptomatic, that they estimate is almost 1/3 of the cases. But that's just my opinion.

Thanks for your opinion dear Julia De Toledo Bagatin and respect your bold sharing too. Actually the members in the study team were highly expert too and the findings are also similar with unofficial hospital records of many countries. Whatever it is, suitable vaccination in such a condition is more difficult when immunity is less and mutation is going on.

We need to develop immunity in the best possible way and need to control the further spread-that's all we want.

HerdImmynity effective for oyr immune system and health because it depends on our surrounding

Thanks for your opinion dear Triya Rachmatika

With documented re-infections and absence of long-lasting immunity in trials beyond a few months, Herd immunity is unlikely. The vaccine is the best and challenging defense to develop.

Think so dear Dr. Pranav and it's a hard reality indeed.

An unknown procedure results , especially as we do not have enough information about the virus or about upcoming mutations in its composition, will it lead to an increase in its ferocity or versa?

So far we know, it's changing and immunity development is not that satisfactory. We need more sophisticated vaccine covering the virulent strains and until then self protection might be the best way to save us as there is no recognized treatment too to cure from it. Thanks for sharing dear Zaid Ali

The implications are clearly beyond just an idea. it may work for other cases, but not for a novel disease.

I have a paper accepted on this topic which will be published in Oct 2020 issue.

Thanks for sharing your opinion sir Ali Cheshmehzangi

Without vaccines, to achieve a high percentage of immunity in the population will mean a large part of the population must be infected. This will cost the lives of many many! Certainly, this is not a way to handle infectious diseases! Therefore, must try every mean to stop/ decelerate the speed of spread and find effective treatments as quickly as possible.

Even with vaccines, it is very difficult to achieve the high percentage of immunity, as (1) some people may refuse to be vaccinated; (2) due to high cost of vaccine and operation costs, many people around the world will never have the chance for the vaccine; (3) viruses mutated quickly and a vaccine for a particular disease will become ineffective very soon, and to "renew" the immunity, new vaccine and vaccinations to a high percentage of the population is needed.

Think so dear Leung Tak Ching and it will take more time too.

Thanks for your contribution! I agree that's the bottom line is:

Can we manage prophylactic therapy in COVID-19 patients to prevent severe illness complications?

Many patients with COVID-19 have thromboembolic complications that worsen their prognosis. Herein, the authors propose a modified version of the CHA 2 DS 2-VASc score, including 1 point for COVID-19, so that prophylaxis to protect against thromboembolic events would be indicated before the condition becomes severe. The advantages of this modification would be prevention of the patient' s condition worsening due to thromboembolic problems and reduction of the likelihood of a need for intensive care and mechanical ventilation, reducing mortality.

Prophylactic therapy in COVID-19 is another important issue in health management, dear sir Paulo Eduardo Ocke Reis and we are actually talking about confusion in herd immunity here. Prevention is the best way to reduce the burden of morbidity and mortality in current situation of COVID-19.

You are right, there are so many problems in COVID-19 that they will not let all clinicians and scientists fall asleep for a long time.

Good luck

Absolutely sir Vladimir A. Kulchitsky and confusion and controversy make it more difficult to find a solution.

It is imperative that everyone feel responsible

Absolutely sir Yousif Yaqoob Shahtha . Global unity is urgent to fight against this unseen enemy as it's beyond borders and already caused huge loss in global economy.

Without vaccines it may not work well, Agree here in this point.

Think so dear Muhammad Shahid Iqbal but the vaccine development is also so difficult due to many strains and continuous mutation of Corona virus.

But, we have no other choice instead, we can not afford even baseline death rate expected in other option exposing our 70% population to the disease.

Your point is valid for mutation but many refrences for effectiveness are there in case of viral diseases.

You can read the news of BBC, dear Muhammad Shahid Iqbal

How close are we to a vaccine?

One would think that a fall in the number of cases of coronavirus infection in the UK is good news all round.

However, there is one area in which it is actually rather bad news – efforts to develop a vaccine.

On Sunday Prof Robin Shattock, who is leading research into a vaccine at London’s Imperial College, admitted that the chances of a vaccine being available in September - as ministers had hoped - are now extremely low.

And last month Prof Sarah Gilbert, who is leading the UK’s other leading vaccine trial at Oxford University, told the House of Lords Science and Technology committee low transmission rates were also holding up progress for her team.

The problem is that a sufficient number of volunteers have to be exposed to the virus to see whether a vaccine protects them or not.

If their chances of being in contact with an infected person are low, it will take a long time to demonstrate the efficacy of a vaccine candidate.

Professor Gilbert told the committee: “We now have essentially a very large safety immunogenicity study running in the UK with little chance, frankly, of determining efficacy.”

About 200 groups around the world are working on vaccines and 18 are now being tested on people in clinical trials.

Most experts believe that huge international effort will turn up an effective vaccine – but not before the middle of next year.

Even that would represent a major scientific achievement. There are no guarantees.

Herd immunity works on the theory that previous exposure prevents subsequent reinfection and spread of disease. Already stated in the response 5% is not sufficient. Early paper from Kings Preprint Longitudinal evaluation and decline of antibody responses in...

shows antibody titres dropping post infection but still unknown titre that will confer immunity post infection or with a potential vaccine?

Thanks for nice sharing sir Charles Delany

Very interesting question. I prefer to look at herd immunity from a protective point of view. That so many people are practicing preventive measures for COVID-19, that the few who do not practice will be protected from contracting the virus. If majority of people wear face masks, sanitise hands frequently and keep social distance, then the probability that those who get in contact with the virus will be low, hence herd immunity. Well this is a hypothesis. My two scents on the topic. Muhammed Ashraful Alam thank you for sharing.

So far we know, it's changing and immunity development is not that satisfactory. We need more sophisticated vaccine covering the virulent strains and until then self protection might be the best way to save us as there is no recognized treatment too to cure from it. Thanks for sharing dear Brenda Ayugi .

If true that IgG anti SARS.CoV2 levels decrease over time ( this is also my experience), it means that the immune response is temporary, and that the vaccine will have to raise a response to multiple epitopes to give protection against infection and re-infection. No herd immunity !!

It's a hard reality sir Gianfranco Ferraccioli and you can see the news of The Guardian too.

Immunity to Covid-19 could be lost in months, UK study suggests

Exclusive: King’s College London team found steep drops in patients’ antibody levels three months after infection

12 July 2020, The Guardian

I believe that Herd immunity is the alone way out ! The valuable population will be affected for example; The sick, elderly, or the disable human will die.

I agree with Angie Bugeja

Herd immunity is the alone way out !

The sick, elderly, or the disable human will die.

Every life is precious and the immunity is not the prolonged one so far experts say. Thanks for your opinion dear Angie Bugeja and Raja Osaily and without vaccination it's quite impossible to develop herd immunity in current situation. Even the vaccine development is facing crisis too in different strains and continuous mutation.

It's a dilemma actually. Actually it depends on many issues even on the country context. Chance of reinfection is another issue here.

Health experts don't yet know whether we really do become immune to COVID-19 after we're infected. And if we do become immune, we don't know how long that might last.

I think there are still too many unanswered questions to risk a widespread herd immunity policy. However, I am not an expert in this field. My expertise lies in Palliative Medicine and this has been challenging enough.

Yes, of course and thanks for sharing your opinion dear Mairi Armstrong

I think that the term "herd immunity" is more or less obsolete in the case of COVID-19 because after a corona infection the immunity apparently lasts only a few months.

https://www.nature.com/articles/d41586-020-01989-z

Think so dear Frank T. Edelmann and health experts don't yet know whether we really do become immune to COVID-19 after we're infected. And if we do become immune, we don't know how long that might last.

I think that "herd immunity" depends also on the previous types of vaccines that the people have taken before this pandemic.

May be but not yet any significant relationship has been described with previous vaccination dear Rafid A. Abdullah

Reading from clinical publications and following up from experts (though not an expert in the area) I feel that there are gaps to fill in on what the virus is and what it isnt out of which herd immunity cannot be relevant.

Yes, you are right dear Andrew Omari Shirima and WHO is still trying to confirm the origin and transmission of Corona virus. Their team arrived China in this week.

It seems it is not all a matter of antibodies. There is Dr Sette in San Diago that found crossed immunity with cold coronavirus, that triggers TCD4, which in turn protects against COVID-19.

So herd immunity would be difficult to track, if only mesuring antibodies.

Nice sharing indeed and it's another aspect indeed dear Marie-Hélène Lessard and if it's more specific one then it would be better as the crossed immunity with cold coronavirus may not be applicable for everywhere.

It seems our knowledge changes rapidly. There are a number of studies now suggest that antibody responses to Covid-19 infection do not last very long - about three months. There can be no herd/population immunity from natural infections unless longer lasting immunity occurs.

Not even a vaccine entirely solves the coronavirus problem. Influenza has an immune response of about 4 months, so re-vaccination is sometimes considered. Influenza still kills many susceptible people each year, and each year the vaccine has to be changed. We still lack an effective treatment for influenza. The best we may be able to do for Covid-19 may be to reduce it to the occurrence level of Influenza, but, that would also require a treatment more effective than we currently have for influenza, otherwise the fact that it is roughly 10 times more lethal will still bring high death rates and a lot of disability.

Immunity from other, earlier infections, such as colds, may have some effect in retrospective studies but the key question is how much. Infecting people with other diseases may make the initial responses to corona virus worse for a significant proportion of patients while protecting only a small proportion, and it would still show benefit in retrospective studies.

In any case, responses to earlier infections by agents other than covid-19 are basically 'vaccination' responses and the question is how long do these last in Covid-19?

Think so dear Robert Young and health experts are also confused actually. They don't yet know whether we really do become immune to COVID-19 after we're infected. And if we do become immune, we don't know how long that might last.

… 

It seems that immunity via antibodies will not be permanent. Whether there is longer-lasting immunity via T cells, remains to be seen.

The problem with herd immunity is that if it is to be achieved via catching the disease, it cannot be had in a short time unless one lets infections run freely, which will lead to many deaths. If one keeps the effective reproduction factor near one and the number of infected persons below the acceptable level defined by the respective health system not becoming overcharged, then it takes at least a year to get to herd immunity.

On the other hand, herd immunity via a vaccine may not work at all or not permanently, if it is antibody-based.

Thanks for nice sharing sir K. Kassner and I do agree.

Nice share. I agree it's not effective.

Thanks for your opinion sir Beibei Du and and health experts are also confused actually. They don't yet know whether we really do become immune to COVID-19 after we're infected. And if we do become immune, we don't know how long that might last.

I think there should be heavy arguments why herd immunity should NOT be possible. The fact that it is stated that herd immunity is not possible due to a low antibody prevalence is not sufficient. First, it has been shown that cellular specific immunity is possible and could be added to the concept of herd-immunity. Second, perhaps there is a problem with antibody testing. Third, epidemiologic data should be given more attention, it seems after an outbreak, even if antibody testing shows only low prevalence, the number of new infections behaves as if herd immunity (or nearly) is already present!

Thanks for your kind opinion sir Alvaro Daschner . If it's nearly herd immunity then how it's possible to confirm >200,000 new cases every day across the world even in inadequate testing in most of the countries. Furthermore, health experts don't yet know whether we really do become immune to COVID-19 after we're infected. And if we do become immune, we don't know how long that might last.

Any opinion is premature unless supported by reliable data. The problem at the moment is knowing if it is possible to achieve an immunization, how long it lasts and if the virus undergoes important mutations.

Yes, I do agree sir Matteo Nioi

Yes I do agree sir

Thanks for your kind opinion sir Kanishka Navin Guru

Nice share. I agree with you.

I agree with you. Nice share

Thanks dear Sankar Panthi

Thanks dear Ibrahim Mohamed

Herd immunity can only have a limited “protective function” in the event that a Country allows the free circulation of “potentially contagious patients”

Thanks for your kind sharing sir Pietro Emanuele Napoli and the problem is that health experts don't yet know whether we really do become immune to COVID-19 after we're infected. And if we do become immune, we don't know how long that might last.

Pietro Emanuele Napoli even then the term "herd immunity" is a difficult one in the case of COVID-10 as the immunity doesn't last long enough. That's why politician should not speculate about "immunity certificates" as they have done in Germany.

Hong Kong's third wave of cases linked to relaxed restrictions, as experts identify virus mutation

16 July, CNN

“Not only several peaks or waves but mutation has been added to create more panic in Corona crisis: Experience from Hong Kong”

The statement "in the case of COVID-10 as the immunity doesn't last long enough".it's a pretty strong. Could you please post the articles or studies from which this data emerges? Of course, just in case it is in magazines in WOS ... @FrankTmEdelmann

Everyday new studies are coming....just follow the BBC, CNN then you can find these papers too. The findings are quite similar in Spain, UK, Hong Kong etc. Matteo Nioi

In fact, I asked for the exact source, not journalistic but academic. It seems to me that at the moment 23 trials are underway in the human experimentation phase .....