Probability that covid will become endemic

[LearningMachine]

Some folks in the medical and academic communities believe that there is a good chance Covid will end up becoming an endemic like the common cold or the flu, which needs a new vaccine every year.

Wondering if anyone in the group has looked into credible sources to help figure out the probability range for this happening.  Once we know the probability range, if the high end of the probability range is high enough, we can talk about potential implications to airlines, remote work, density in cities, etc.

Here are some articles I've run into:
* https://www.huffingtonpost.co.uk/entry/covid-19-endemic-pandemic-epidemic_uk_5f99a2abc5b6aab57a0eb788?guccounter=1&guce_referrer=aHR0cHM6Ly93d3cuZ29vZ2xlLmNvbS8&guce_referrer_sig=AQAAAFY2D4Q9zh3-O_LifL8Km8l7eait0vUsQ5u9Sxy6bWucWEPwkcijmsuJlk64j2OaBsW8pgUSJLPoqSvXmyaze-412bD9YFU55UvwlZJnlWgodlmVyuMuVErL-iV3MShTAg32rSybeVNwo5lX7mQs8x9perwMjJ9083wvT0KzdJGZ
* https://science.sciencemag.org/content/370/6516/527
* https://www.publichealth.columbia.edu/public-health-now/news/will-covid-19-virus-become-endemic
* https://www.sciencedaily.com/releases/2020/10/201015101820.htm#:~:text=Evidence%20suggests%20COVID%2D19%20could,temperate%20regions%20similar%20to%20influenza.

[clutch]

Even if it becomes endemic, things will return to normal. Both the transmission rate and fatality rate will continue to lower (with vaccine and better treatment), making this another type of the common flu. Not to mention, we will reach some form of herd immunity -- as it did with (and ended) the Spanish flu. We haven't changed much of our behaviors because of the flu.

The only implication/change I would like to see is on the long-term care front. Not only because of COVID, but is this really how our society should deal with older people -- basically putting them in a prison?

[Viking]

Great question. There is still so much we do not know. Like what happens if the virus mutates?

So while the news from Pfizer and Moderna is certainly encouraging there remain many forks in the road ahead.

[frank87]

Great question. There is still so much we do not know. Like what happens if the virus mutates?

So while the news from Pfizer and Moderna is certainly encouraging there remain many forks in the road ahead.

The flu mutates frequently. All viruses mutate.

[KCLarkin]

Preprint released today suggests long-term immunity for 90% of people. Perhaps for decades as seen with SARS.

Comparisons with flu are misplaced on all levels.

So, in summary:
1. Covid is certain to become endemic
2. Between vaccines and acquired immunity this virus will not be material beyond 2022

[LearningMachine]

Preprint released today suggests long-term immunity for 90% of people. Perhaps for decades as seen with SARS.

Comparisons with flu are misplaced on all levels.

So, in summary:
1. Covid is certain to become endemic
2. Between vaccines and acquired immunity this virus will not be material beyond 2022

Thanks KCLarkin, would it be possible to share the link to the source? 

Which one of the below are you saying?

• (a) 100% certainty that Covid-19 coronavirus will not mutate, unlike the flu coronaviruses, or
• (b) 100% certainty that the same vaccine we get once for Covid-19 coronavirus will be able to provide immunity against all mutations of Covid-19 coronavirus, unlike the vaccine for flu coronaviruses.

[LearningMachine]

Even if it becomes endemic, things will return to normal. Both the transmission rate and fatality rate will continue to lower (with vaccine and better treatment), making this another type of the common flu. Not to mention, we will reach some form of herd immunity -- as it did with (and ended) the Spanish flu. We haven't changed much of our behaviors because of the flu.

How is the transmission rate, that is, R0, going to go down for mutations of Covid-19 coronavirus with vaccine and better treatment?

Flu has an R0 of about 1.3, i.e. one person can spread it to 1.3 people on average.
Spanish Flu had an R0 about 2.2 to 2.9, and effectively lowered further due to less travel sometime after World War I was over.
Covid-19 coronavirus strains have an R0 as high as 5 or higher, exacerbated further by dense populations and travel.

Do we know of other ways of lowering R0 for Covid-19 strains other than behavior change?  We cannot say with 100% certainty that herd immunity will continue to provide immunity for mutated strains of Covid-19.  We do know that herd immunity does not provide immunity for mutated strains of flu coronaviruses.

[clutch]

Even if it becomes endemic, things will return to normal. Both the transmission rate and fatality rate will continue to lower (with vaccine and better treatment), making this another type of the common flu. Not to mention, we will reach some form of herd immunity -- as it did with (and ended) the Spanish flu. We haven't changed much of our behaviors because of the flu.

How is the transmission rate, that is, R0, going to go down for mutations of Covid-19 coronavirus with vaccine and better treatment. 

Flu has an R0 of about 1.3, i.e. one person can spread it to 1.3 people on average.
Covid-19 coronavirus strains have an R0 as high as 5 or higher.

Do we know of other ways of lowering R0 for Covid-19 strains other than behavior change?  We cannot say with 100% certainty that herd immunity will continue to provide immunity for mutated strains of Covid-19.  We do know that herd immunity does not provide immunity for mutated strains of flu coronaviruses.

Vaccines. The transmission rate will go lower if more people are immune to it. Isn't that obvious?

If the virus mutates and presents a serious threat again, I'm sure that we will develop another vaccine that works.

[LearningMachine]

Even if it becomes endemic, things will return to normal. Both the transmission rate and fatality rate will continue to lower (with vaccine and better treatment), making this another type of the common flu. Not to mention, we will reach some form of herd immunity -- as it did with (and ended) the Spanish flu. We haven't changed much of our behaviors because of the flu.

How is the transmission rate, that is, R0, going to go down for mutations of Covid-19 coronavirus with vaccine and better treatment. 

Flu has an R0 of about 1.3, i.e. one person can spread it to 1.3 people on average.
Covid-19 coronavirus strains have an R0 as high as 5 or higher.

Do we know of other ways of lowering R0 for Covid-19 strains other than behavior change?  We cannot say with 100% certainty that herd immunity will continue to provide immunity for mutated strains of Covid-19.  We do know that herd immunity does not provide immunity for mutated strains of flu coronaviruses.

Vaccines. The transmission rate will go lower if more people are immune to it. Isn't that obvious?

If the virus mutates and presents a serious threat again, I'm sure that we will develop another vaccine that works.

Hence, my question at the start of the thread, i.e. what is the probability that we would need a vaccine every year?  So, you agree that the probability of that is non-zero?

[KCLarkin]

Which one of the below are you saying?

• (a) 100% certainty that Covid-19 coronavirus will not mutate, unlike the flu coronaviruses, or
• (b) 100% certainty that the same vaccine we get once for Covid-19 coronavirus will be able to provide immunity against all mutations of Covid-19 coronavirus, unlike the vaccine for flu coronaviruses.

https://www.biorxiv.org/content/10.1101/2020.11.15.383323v1

100% certainty that Covid-19 will mutate but at a much slower rate than influenza viruses (we should be grateful this isn't "just the flu").

To simplify, let's assume the rate of mutation is related to mutations during the following:
1. Replications within a host (human or animal)
2. Jumping between hosts
3. Jumping between species

This suggests that rate of mutation will be highest at the peak of the pandemic when the virus is replicating rapidly in people and jumping rapidly between hosts. We've had perhaps trillions of replications, yet vaccines are showing 90% efficiency. This shows that the virus is not mutating rapidly (which is also shown in genetic tracing).

You could foresee some random mutation that allows Covid-19 to evade the vaccine, but the probability is related to the number of mutations. So the likelihood of a dangerous mutation occurring after June 2021 is much lower than one occurring in 2020.

Edit to add: So that suggests you won't need a yearly vaccine solely due to mutations. You might still need one for waning immunity, but the preprint above suggests immunity could be reasonably long-lived.