Logic behind second wave prediction

[BumbleWumble]

What is the actual logic behind the prediction that there will be a second wave?

I know it's based on what happened with the Spanish Flu but wasn't that influenced by soldiers returning from. WW1?

Why would this virus just take a break so to speak before returning with a vengeance? As opposed to simply carrying on infecting people consistently whereever it can.

The likelihood will be the combination of easing lockdown, ignoring guidance, colder weather, and the virus still being prominently in the community. It usually takes several weeks from infection to dying so by then positive cases have significantly increased.

The positives for a lower death rate are that we are aware of what to look out for, testing, those at highest risk will know to take things very seriously throughout, we have already started to change lifestyles (wfh, supermarket deliveries, social distancing etc), people are cautious and the weakest in our society are likely to have already died from it. Hopefully we will also have a vaccination of some sort as well.

For an actual 2nd outbreak, rather than the theory, take a look at any news channel which will tell you about what is happening in Melbourne.

Why would this virus just take a break so to speak before returning with a vengeance?

It wouldn’t. We were in lockdown which limited the spread. With restrictions lifting, people ignoring social distancing and people spending more time indoors when it gets colder, it will start up again.

It may well be manageable with lock lockdowns though (arguably these could have been tried the first time around too. If London had been locked down early lots of deaths would have been prevented).

Weather
More time inside
Vitamin D levels
Imo you get more ill if you are cold.
Heating/air con.
I notice southern hemisphere started getting more issues once they moved more into winter.

I think the logic is linked to the Spanish flu but it is flawed. We have actually come along way medically since 1918 and that will make a difference. People on here are hung up on individual behaviour and that jogger in the park who cane close to them but actually much bigger issues impact and we are no were near where we were in March. Some reminders

• a huge number of office workers are still working from home and advices to do for the foreseeable.

-big event (premier league crowds, Glastonbury, Olympics, all live theatre still banned with the even saying pantos is unlikely to take place)

• those who know they are vulnerable will continue to be more cautious than in March

-we do have a test and trace system, it may not be perfect but we didn’t even test people with symptoms back in March! Every week 100000 people are being told to isolate because they could spread covid, 100000 people who were not told so in March.

• we do have better treatments, two drugs that can help, not the cure we are looking for but better than March.

All this makes me think a second wave worse than we haVe just had when we had none of these is unlikely! All reduce infection spread even if that lady at Sainsbury’s did get a little close to you!...I think we may see some bumps, localised outbreaks etc but. I think people do not get how unprepared we were in March!

I think it all depends how much we follow guidelines, social distancing, hand washing and avoiding crowds.

@Qasd yes I think this, surely, even with flare ups, there is still many whom are social distancing, WFH, people being slightly germphobic.

@CloudPop

For an actual 2nd outbreak, rather than the theory, take a look at any news channel which will tell you about what is happening in Melbourne.

Exactly this. Australia thought they had pretty much eradicated it then this sudden spike in Melbourne and the need to reintroduce lockdown. The virus is still there. Lockdown broke the chains of transmission so it couldn't spread nearly as widely but it is still capable of spreading once increasing numbers of people are in close contact. This will be worse in autumn/winter when we are spending more time indoors.

I think a full national lockdown again is unlikely though. Hopefully test and trace will be fully established and social distancing measures will continue. There should also be more effective early treatment, such as early oxygen administration, to help manage those who do get it. There appear to be increasing numbers of younger people catching it as they get back to work etc who statistically will be less vulnerable to its effects.

The virus isnt "taking a break" to return with a vengeance. The virus is being held back from spreading as the social restrictions are preventing transmission. As soon as restrictions are lifted and people no longer socially distance, it will spread again unless the number is 0 in the community. Weve only peaked because we made the numbers come down through lockdown. The peak isnt where it would naturally be if we hadnt.

This is why lockdown is such a ridiculous strategy long term. As we see in Germany and Australia the virus will spread again when given the chance. I dont know what the solution is though.

I was told it will be due to colder weather come October and people shut windows, doors and go inside all things, conditions which make viruses easier to spread

Opposed to now, where people are outside, open windows and doors - which is safer due to virus being more difficult to spread in these conditions

The virus hasn’t taken a break from anything.

We’ve been in lockdown so transmission has been significantly reduced.

As things get back to normal, this will increase. Pubs, restaurants, cinemas, shops and most significantly schools (the grounds themselves but also the transport) will be huge transmission points taking the spread out into the community.

Sweden hasn't locked down though and they have peaked (well, deaths are in decline).
So it does seem like there is a saturation rate. Our death rate is higher than theirs so I am inclined to think that we won't get a second wave. But somewhere that hasn't had a proper first wave is still at risk of a second if they don't protect the elderly sufficiently.

Sweden hasn't locked down though and they have peaked (well, deaths are in decline).
So it does seem like there is a saturation rate. Our death rate is higher than theirs so I am inclined to think that we won't get a second wave. But somewhere that hasn't had a proper first wave is still at risk of a second if they don't protect the elderly sufficiently.

Immunity is also a factor. Research suggests that immunity in mild/asymptomatic cases only lasts 3 to 6 months so as that wears off the chance of the virus beginning to multiply more rapidly increases.

@Qasd

Agree with what you posted. I think lockdown has changed many people’s perception of risk enormously, and they forget just how comfortable we were with being socially close to people before Covid. If I recall the month before lockdown I travelled on the tube squashed up against people, went to a theatre sat close to others for two hours, attended a church service with lots of music and singing, went to a packed swimming pool with my children, got into various nearly full lifts, thought nothing of hugging friends and family, and much, much more besides.... Most of us did and thought nothing of it as it’s how 67 million of us had always lived our lives. No wonder Covid exploded!

Those people who then thought that a second wave would be caused by the minority of people failing to fully socially distance at outdoor VE day street parties, a few thousand protesters (many with masks), and busy beaches with people sitting in family groups in the sea breeze, got the risk totally out of proportion. The crazy thing is that some of them think that Covid must therefore be over because that second wave (based on a tiny fraction of our collective social interaction previously) didn’t happen!

Hugh Pennington is not convinced there will be a second wave. Apparently that is only based on the Spanish flu pandemic which doesn’t follow the same pattern as Covid. I think.

Sweden hasn't locked down though and they have peaked

Sweden may not have locked down, but it’s completely wrong to think it just carried on as normal. Social distancing did occur which was sufficient to stop growth but the result that only small fraction have antibodies - it certainly hasn’t got close to achieving the fabled “herd immunity” despite the hopes of one or two of its leaders.

A combination of the fact the UK acted only once Covid had more deeply embedded than it had in Sweden, its high population density, and the fact the public generally aren’t as obedient to advice as in Sweden (few places seem to be), meant that trying to repeat Sweden‘s tactics would likely ended in disaster here.... (and in Sweden
their deaths are massively higher than its Nordic neighbours btw).

lets see USA increases because it opened too soon
Spain shutting down 3 areas
India
& Sweden has increased its shut down
we have had 3 pubs at least who have shut again
Leicester
several in UK which are based in factories/meat processing
Africa has increased outbreaks which like Pakistan & India are not being recorded
to get herd immunity it was stated today you need at least 70% immunity at the moment we have less than 10 (cant remember exact figure) nb this makes sense as measles needs about 90%
Have your flu jab early basically if for no other reason (except for important one of not getting flu because we don't need an epidemic of that) than you are less likely to find yourself isolating because of symptoms

But there are going to be outbreaks until the population is vaccinated @mumwon. And maybe even then. It doesn’t mean that there will be a second wave, although vigilance at keeping on top of outbreaks will be required

There are lots of observations that the virus seems to burn out once about 20% of people have been infected. That 20% varies a bit and there are outliers, but you probably wouldn't see, say, London or New York having a big second wave. But you'll probably get dramatic outbreaks in places where few people have been infected yet, and that will make people panic

Define what is a "second wave" and I can answer your question.

This is a example of a 2nd wave (Indiana, JHU, c19 case counts). Nearly back to what they were before at peak: 2nd wave.

Dunno how OP describes 2nd wave, though.

,,,,

Graphs without any explanation are meaningless. That could be the number of aphids on your Rose's for all we know

Apparently that is only based on the Spanish flu pandemic which doesn’t follow the same pattern as Covid.

All flu pandemics since Spanish Flu (so Asian Flu, Hong Kong Flu, Swine Flu) also lasted two years. Of course there is already immunity in the community to various strains of flu so in 1918 the older population was not as badly affected as the young because they had immunity from a similar flu in the 19th century, and Swine Flu wasn't as big a killer as expected because people over 60 had immunity from a similar Flu strain in the 60s. I think for Flu (where we get long lasting immunity and there are always sections of the community with immunity) it clearly takes about 2 years for enough people to get immunity to a new strain for it to longer be an issue.

But Covid-19 is a coronavirus not influenza. We know we only develop short lasting immunity to the endemic coronaviruses, of about 1-3 years before we are susceptible again. So without a vaccine that confers long lasting immunity we are looking at wave after wave of infection, possibly a seasonal pattern as we see for other respiratory infections and with a yearly vaccination programme and constantly improving treatments.

There are lots of observations that the virus seems to burn out once about 20% of people have been infected.

Where are these observations? Places that have had lots of infections have invariably gone into lockdown, causing the Covid “fire” to be snuffed out, not to burn out.

However, take NYC... antibodies are around the 25% mark I believe. If a portion of those infected recovered using T cells only, then the antibody count would understate the number infected, so NYC could have a significant level of herd immunity. I believe the highest levels of antibodies are in the 40-50% range in Bergamo. That would suggest that, even if Bergamo had full herd immunity (which is unlikely as that would have required the virus to take its natural course in the population which it didn’t due to its lockdown) there remains headroom even in very badly affected places like NYC, and London (bad but significantly less bad than NYC).