Please take a look at the following RG links and PDF attachments.

Article Risk of reactivation or reinfection of novel coronavirus (COVID-19)

Article Recurrence of positive SARS-CoV-2 RNA in COVID-19: A case report

Article Recurrence of COVID-19 after recovery: a case report from Italy

Article A case of a readmitted patient who recovered from COVID-19 i...

Dear Hamed

I hope this helps:

https://www.independent.co.uk/life-style/health-and-families/coronavirus-immunity-reinfection-get-covid-19-twice-sick-spread-relapse-a9400691.html

Yes, already reported many cases.

Yes, some cases are reported.

A possibility is there.

Have a look

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7177092/pdf/main.pdf

Yes, already reported in so many countries.

Yes, some cases are reported, immunity after a previous illness is questionable ???

Yes, it is possible. We are in an unfamiliar area. Some of the researchers say that there is re-acting or relapse in the virus. so there are reinfection cases. Hamed Delam

Dear Dr, Meghdad Abdollahpour-Alitappeh

Thank you

Zarema Obradović

Yes, is there permanent immunity after illness?

There is currently no evidence that people who have recovered from COVID-19 are protected from a second infection.

https://in.reuters.com/article/us-health-coronavirus-who/no-evidence-that-recovered-covid-19-patients-cannot-be-reinfected-who-idINKCN2270FB

Please take a look at the following RG links and PDF attachments.

Article Risk of reactivation or reinfection of novel coronavirus (COVID-19)

Article Recurrence of positive SARS-CoV-2 RNA in COVID-19: A case report

Article Recurrence of COVID-19 after recovery: a case report from Italy

Article A case of a readmitted patient who recovered from COVID-19 i...

That is possible.

Depending on the patient's health condition

احتمال كبير

ظهرت حالات جديدة في بعض الدول ومنها الصين

Yes, it is possible. Some of the researchers say that there is re-acting or relapse in the virus. so there are reinfection cases.

Initial results from a two month antibody testing study have revealed that COVID-19 antibodies remain stable in the blood of the majority of infected individuals almost two months after diagnosis and possibly longer. However, antibodies were not detectable in everyone exposed to the virus.

https://medicalxpress.com/news/2020-06-covid-immune-response-stable-months.html

I'm afraid that's pretty much possible.

Hope this is useful:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7177092/

While RT-PCR re-testing patients for Sars-CoV-2 after they have recovered has been shown to be positive in some patients, there is no evidence that those tests indicate infectious virus. I may well be viral RNA detritus.

Common clinical sense dictates that if a person was symptomatic for Covid-19 infection and has recovered, he/she is immune. All other testing, other than tissue culture for infectious virus, is meaningless.

Some countries have reported reinfection. Personally I think there many issues yet to be resolved about Sars- CoV-2 infection and this is one of them.

More research is needed to confirm re-infection.

Yes he can be infected because there was no scientific backing to prove that such person develop required antibodies that will give him complete immunity. Like the ones in meningitis.

Of course, a person will be affected again. As doctors are saying that there is no evidence that will proof an infected person never be affected again. Because it's a virus and when a cured people will come closer to infected person so it will be happened. Moreover, People need vaccination if it is possible then we can say that it never be happened again.

Past medical science with other corona viruses and other respiratory viruses indicate that a truly symptomatic person infected with a virus and revocered is immune. Such survival immunity is far better than any vaccination. Of course "herd immunity" is a rsik for fatal infections in those w. serious comorbid conditions.

There are some reports that confirm this possibility

Yes, so many cases reported already.

It looks to me that many people are getting confused with the terms used. The fact that a clinically healed patient is still intermittently positive, and possibly spreading the virus for several weeks, is not unheard of in infectious diseases. This is not evidence that the patient got re-infected. I am not saying this is not possible, but I have not seen any supporting evidence so far.

I agree on the fact that there is still much we do not know about this virus, and it will likely be the subject of research for years to come.

Nicholas Bachynsky :

I always like your dry, straight to the point, answers 😄👍

Best,

Max

The possibility of a second infection could not be ruled out.

Yes

This possibility exists but fortunately is very rare event

I concur with the responses. I just suggest that:

The science of Covid-19 is changing. For example, the virus seems to mutate, some of the information may not be peer-reviewed or even incorrectly reviewed. Verification of the information to be used to understand what is actually happening and why is critical before going ahead with accepting the evidence that one may wish to use.

The research by researchers at Chongqing Medical University, ..

Read more at: http://timesofindia.indiatimes.com/articleshow/76521166.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst

Hamed Delam at the moment, not enough pieces of evidence available to confirm nor negate the notion that people who have recovered from COVID-19 are protected from a second infection.

Yes. There is no suspected evidence of the incidence but if we consider the nature of virus, it is possible, if person is exposed to the same conditions again, may get infected, unless, the vaccination against the virus is introduced and injected into the previously infected body.

I think at this time no evidence which justifies there will be the probability of reinfection

Reinfection, reactivation of SARS-CoV-2 and false negatives in final reports can be possible reasons for getting COVID-19 again.....

*There are evidences that in certain SARS COV 2 viruses’ after infection IgG titres go down just in 2-3 months, as a result there is no long term acquired immunity and person becomes susceptible for reinfection...( This logic will fail the idea of development of long term effective vaccine)...

*sometimes virus go dormant in certain deeper body tissues and reactivate again after some time....( This logic will fail the concept of herd immunity)...

*Also sometimes results at discharge are False Negative....which in due course give a false impression that there is reactivation of virus again....( This reasoning will lead to innovation of newer methods to collect sample from deeper lung structures etc)...

All the above 3 reasons were revealed in certain cases which were found second time positive for COVID-19 after their first discharge from health care facility..( Interestingly these cases neither reported any contact history nor travel history.....)

Ref: MedRxiv and bioRxiv preprint server publications... mostly not peer reviewed....

Data gathered from studies of China, South Korea, Norway etc....

There has NOT been ONE CASE where a symptomatic Covid-19 patient (not just a positive carrier) has recovered and got re-infected again. This is a respiratory virus, albeit novel, but it behaves like all the others (>200) that cause the seasonal flu. We will eventually all get in contact with it. Some of will get a cold, others nothing, some will get sick, and some will die. Just like has happened with past Flu epidemics (Spanish Flu, Swine Flu, Hong Kong Flu). Yearly Flu vaccinations are only 20%-40% effective (some say less). If this one is ever developed it will be no better. Mother Nature keeps marching on.......

It is possible and is very important to be aware of this possibility and to act early and in an efficient way to short the local spread again

Yes, anyone can be infected recurrently by SARS-CoV-2, fortunately the rate isn't so noteworthy. You can get detail about the fact from the case report study: Article Recurrence of COVID-19 after recovery: a case report from Italy

Yes, though there is no such evidence that the previous infection leads to the passive immunity to the body, but at a particular scenario the probability of the getting infection might reduce to half. Exposure to the virus will lead to the disease, if symptoms doesn't persist exposure may result the individual to become a vector of the disease (only happens in case of strong mucosal reaction) which is more problematic situation. So all preventative measures should be taken during and post infection to prevent it's reoccurrence.

As the old saying goes "You can run (distance, isolate, wear face masks), but you can't hide (eventually the flattend area under the curve will equal the peak area over time)". Sooner or later this will be old news and part and parcel of all the other pathogens that humans carry in their upper respiratory tract protected from serious infections by heard immunity.

I think that no. Scientists said that he will have antibodies.

Governments are starting to lift restrictions and some are considering “immunity passports”, where all restrictions are lifted for those previously infected.

But are you immune from COVID-19 if you’ve already been infected?

Some infections never recur once you’ve had them, such as measles and smallpox. But you can get plenty of others again, such as influenza and tetanus.

So far, research suggests at least a proportion of people who have had COVID-19 will be protected from another infection – at least initially. But the science is far from certain. Here’s what we know so far.

Why do some people test positive again?

There are reports from different countries of people hospitalised with COVID-19 who tested negative when they were discharged, before testing positive again.

However, a study from China found those who retested positive didn’t get any sicker. This suggests these people were intermittently shedding the virus and were at the tail end of their original illness, rather than getting a new COVID-19 infection.

I guess there is no evidence if he returns or not.

Unfortunately, a person can get infected with in 3 months as some studies say , other studies mentioned a period of 6 months for re-infection

Yes it is possible, though the debate is on and reports of possible re-infection.

Yes, of course. There are many reported cases all over the world

There is NO credible case in which a symptomatic Covid-19 patient recovered and got re-infected. Not a one. This does not apply to those that are postive for the virus but asymptomatic, nor those with or without antibodies. The anamnestic response and cellular (Tcell) immunity may well be in play and the be the dominant immune mechanisms. Many asymptomatic false poaitives have gotten infected, but they were not positive and symptomatic to begin with.

Actually,till now there is no strong dependent evidence that previously cured patient from covid19 to be protected from reinfection so we must take precaution by wearing protective equipments as mask, visor and gloves when go out and don't forget the best protective measure :hand washing,hand washing.

best regard

It has been described. Generally , the clinical course is milder than the first infection

On about COVID-19 dear researchers is it possible we know the following concepts.

1. False - negative results

2. False - positive results

If we understand this, then sensitivity and specifity of this pandemic can be know

Till now there is no strong evidence that previously cured patient from Covid-19 to be protected from reinfection, so we must take precaution by wearing protective equipments as mask, visor and gloves when go out ; the best thing is hand hygiene.

the virus is still new for many, as reported by some countries, in different populations there have been reinfection of patients who had previously become ill, therefore we can observe the human susceptibility to the virus, in addition we must remember that mutations can occur so Both at any time we could be exposed to infection or reinfection or associated superinfection. I think there is still a lot to study from COVID-19.

As the virus becomes more endemic and herd immunity becomes a reality it will follow a pattern similar to the other Flu seasonal viral pathogens. On a clinical basis, those that have recovered from clinical infections (symptomatic) of Covid-19 are immune from re-infection as much as people are immune to Influenza A and other repsiratory viral agents.

As the virus is on process of antigenic shift and drift the new infection is likely.

Flu vaccines are only 40% effective (some say 20% or less). Herd immunity is best, but viral mutation rates and antigen drift does cause repeat infections. Most of the viral respiratory pathogens become endemic, we carry them and when conditions are ripe we get re-infcted with symptoms. Mother nature is an equal opportunity employer!

The following study reveals that people who have recovered from COVID-19 may lose their immunity to the disease within months.

Preprint Longitudinal evaluation and decline of antibody responses in...

Of course, it is possible and there are many cases referred from different countries

Please have a look at the link below:

Article RECURRENT COVID-19 INFECTION IN RECOVERED PATIENTS (A CRITICAL REVIEW)

A person who has previously been infected with the SARS-CoV-2 Coronavirus, regardless of whether they have had Covid-19, whether they have had symptoms of the disease or not, whether they know that they have had the SARS-CoV-2 Coronavirus or not, have already acquired a natural the body's resistance, the immune system has made antibodies. In such a situation, if the same person has repeated contact with exactly the same type of SARS-CoV-2 Coronavirus as before, he should not get sick with Covid-19. But this virus, like other viruses, is constantly mutating, so it cannot be ruled out that during the second and subsequent waves of the pandemic, a new and different type of Coronavirus may be spreading globally and will be new enough to be a new type of virus for the human immune system. Then certain symptoms related to the new infection may appear. But these are only theoretical considerations. How it will be in practice, it remains to be seen in a few months or later.

Best regards,

Dariusz Prokopowicz

till now, studies say the previous infection give 3 month immunity against new infection.

It is not a frequent event, but is possible

There are found few cases.

Please have a look at the link below:

Article Clinical recurrences of COVID-19 symptoms after recovery: Vi...

The possibilities are there.

No one who tested positive for Covid-19 and was symptomatic, who recovered from Covid-19 has gotten a symptomatic re-infection.

Yes sometimes may occur but with less intensity and better progonsis in general

The immune response, including duration of immunity, to SARS-CoV-2 infection is not yet understood. Patients infected with other betacoronaviruses (MERS-CoV, HCoV-OC43), the genus to which SARS-CoV-2 belongs, are unlikely to be re-infected shortly (e.g., 3 months or more) after they recover. However, more information is needed to know whether similar immune protection will be observed for patients with COVID-19.

Maybe

This may happen but occurs in relatively few cases

Please see the link below.

https://www.news-medical.net/news/20200720/Doctor-in-Israel-reinfected-with-COVID-19-three-months-after-recovering.aspx

Yes,

Yes, there is every possibility of being infected again. As because:

i. The antibody that develops due to attack wanes with time

ii. All of the patients do not develop protective antibodies.

Please see this most recent link entitled:

First case of coronavirus reinfection confirmed, researchers say

https://www.livescience.com/coronavirus-confirmed-case-reinfection.html

A man in Hong Kong is the first with a confirmed reinfection with the novel coronavirus, a new study suggests.

Please have a look at the following link:

https://www.sciencenews.org/article/coronavirus-covid-19-first-case-reinfection-man-hong-kong

Yes, this study (see link) shows that 11 virologically-confirmed COVID-19 patients having experienced a second clinically- and virologically-confirmed acute COVID-19 episode.

Article Clinical recurrences of COVID-19 symptoms after recovery: Vi...

There is a possibility but very rare in frfequency

According to the link shown below "Patients who have recovered from COVID-19 should not assume that they will not be infected again"

https://fortune.com/2020/08/25/first-covid-reinfection-hong-kong-coronavirus-vaccine/

Yes of cause, Recently, It was reported many cases. Why? the active immunity developed by Covid 19 viral infection is very weak an short lived. So, a person

survived, can get the disease again if infected.

Samarakoon Mudiyanselage Samantha Samarakoon yes, you are right. I'm not an expert, but you can also get a common cold again and again.

Hamed Delam Yes. Now its proven truth.

Kindly check this link https://www.healthline.com/health-news/people-reinfected-with-covid-19-werent-infectious

Thanks

Yes, US officials just reported the first reinfection case in the USA

https://www.dw.com/en/coronavirus-digest-us-officials-report-first-reinfection-case/a-54748545

Yes can be occur but fortunately in very few cases and with a good prognosis

Dear Hermann Gruenwald this would definitely be good news if reinfections showed only mild symptoms. However, I just found a report showing the opposite:

US Man Reinfected With COVID Suffers Worse Symptoms

https://www.infectioncontroltoday.com/view/us-man-reinfected-with-covid-suffers-more-severe-symptoms

Clearly more research needs to be done.

Yes, but it can not have much effect.

Yes it seems possible. Lately I could read in the scientific press “In Hong Kong a 33 year old man was tested positive for the SARS-COV-2 corona virus 4 months after his first infection. Analyses made it possible to exclude a reactivation of the first infection”

According to some sources, it is possible

kindly refer to both articles:

1. https://www.healthline.com/health-news/people-reinfected-with-covid-19-werent-infectious

2. https://medicalxpress.com/news/2020-05-survivors-reinfected-coronavirus.html

J Oral Microbiol. 2013; 5: 10.3402/jom.v5i0.22766.

Published online 2013 Oct 25. doi: 10.3402/jom.v5i0.22766

Reference Article depicting “ Latency & Reactivation “ of different viruses.....

Definitely ....reactivation/ reinfection (from same strain or different strain) along with previous & latest immunoglobulin titres are to be addressed simultaneously (but distinctly) to rule out possibilities.....

According to this recent link "A case of coronavirus reinfection shows the complexities of the pandemic"

https://www.theverge.com/2020/8/29/21406019/covid-19-coronavirus-reinfection-immunity-antibodies-vaccine-test

Yes but very rare!

It can happens but is very unusual really

Dear Hamed Delam please see this interesting link entitled Scientists are reporting several cases of Covid-19 reinfection — but the implications are complicated

https://www.statnews.com/2020/08/28/covid-19-reinfection-implications/

Apparently NO.

But different strains with much more devastating property may infect again a corona patient if his/her immunity power still remains under developed.

I think yes. Some body already reinfected