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OPINION: Will there be a second wave of COVID19?

Our own Ben Harris was asked the possibility of a second wave, and here is his response:

“I’m curious, what does Ben think of the "Second Wave" that is projected to happen in the fall?”

The short answer is, of course, nobody knows.

An initial main concern re COVID-19, in my mind at least, was that any second wave could potentially be a second wave caused by a significant new strain mutation, as has happened with previous main influenza pandemics, and these have sometimes been a considerable length of time later:

 

BUT to date COVID-19 (like influenza, and measles, also RNA viruses) has mutated very little (2 base pairs only of 10-20,000 or so) per month, which is not like influenza at all, and so unlikely to be a second wave mutation risk.

 

So, second wave potential with same strain risk?

This will likely be predicated on a number of factors including:

  • Human behaviors:  as it sweeps through the USA relatively unchecked, fear increases, so people generally respond with more or less social distancing, masks, isolations, etc.  As the fear subsides, post any incidence peaks of infection and subsequent declines, so fears and associated risk averse behaviors reduce, allowing resurgence of the same strain

  • COVID-19 virus  environmental survival:  colder less humid/drier (<45% humidity) conditions favor environmental survival for longer of this usually relatively fragile RNA virus - usually ~30 hours on an absorbent surface, 60 hrs stainless steel, 70 hrs plastic.  In addition, and likely more importantly, colder weather (autumn onwards) drives people indoors more, socializing together/closer more, and COVID-19 primarily spread by sharing the same air of an infected person - even at a (room) distance, c.f. like smoke, from a source (infected person) given time in the same room, sufficient cumulative virus to cause an infectious dose is more likely to be breathed in - thus increased healthcare worker deaths, even when wearing N95 masks worn, which are good but only down to 0.3microns, and virus are 10-100 times smaller.  N95's filter 95% of 0.3 micron particles, and COVID-19 virus is often/usually in droplets or vapor aerosols larger than 0.3 microns, so filtered, but NOT when that vapor (low humidity) evaporates off leaving 'naked' tiny virus particles to float anywhere and also 'sail through a mask' 

  • Herd immunity and immune responses  As more people catch COVID-19 (with or without symptoms) they develop antibodies.  Hopefully these will be protective (not all antibodies are, e.g. if the antibodies are not against a non pathogenic essential component, say viral nuclear membrane rather than essential spike for attachment, they will not be protective).  Currently it looks as though antibodies will be protective though.  Then how long will they be protective for??    Monkey studies indicate perhaps a year, at least for antibodies ( but we can have relatively hard to measure cellular immunity also). And we know 'cold' coronaviruses lose their immunity after about a year, and then we catch a cold again - but colds are now quite mild, likely compared to when we first caught colds when they would have been very severe - and may in fact have caused the previously assumed influenza   'A', 1889-92 pandemic in graph above. 

 

Currently it would seem a plausible likelihood that everyone on earth will be exposed to COVID-19, one way or another, over the next 1-3 years or so, faster when less active mitigation measures, and likely in same strain waves which are both regionally and seasonally affected.  Then everyone is likely to have some residual immunity, so the next exposure will likely not be as severe as when first exposed.

Somewhere along that timeline, hopefully a vaccine and or treatment will be available.

 

How effective that vaccine is,  and for which age groups, and for how long is it effective,  will be key.

 

Currently measles vaccine is 97% effective over a lifetime after two shots, and 95% population take up of vaccine.

 

But influenza vaccine only about 20% efficacy in an average year for > 65 year olds, 60% efficacy for < 65 year olds and only lasts for about 12 months - but influenza is always mutating far more than COVID-19 (about four times faster on current evidence), so hopefully that is not the trajectory expectation for COVID19. 

 

https://www.nejm.org/doi/full/10.1056/NEJMc2004973

 
 
 

We must also remember that in perspective, and in percentage terms rather than absolute numbers which seem more horrifying, the COVID-19 will likely be like a 'bad flu year' mortality rates, perhaps 0.1+% mortality.

Each 100,000 deaths in the USA is 'only' 0.03% of the USA population.

Currently USA deaths 76,421. 

 

But  it is the elderly who bare the brunt of those deaths, 80-90%, and they need protecting most, especially in rest homes and especially if co-morbidities especially those which increased ACE-2 receptor sites (which COVID-19 primarily attaches to in the upper and lower respiratory tract and also in the bowel), such as pulmonary, heart, blood pressure, renal, diabetes, obesity related conditions.  In turn all these ACE-2 receptor sites, along with natural increased inflammatory responses in the elderly, contribute to the main pathogenic process of COVID-19, our highly activated immune response to it which causes the main clinical response to contend with.

Of interest, those countries with more endemic intestinal worms (e.g. Africa), seem to have fewer COVID-19 casualties, to date at least, and worms have a known immune system moderating effect.  So, as 'we have cleaned up ourselves' with modern medicine in the industrialized world, this may be a legacy reality to contend with (as with more inflammatory conditions like eczema and dermatitis, as well as more autoimmune conditions like MS, Crohns, IBD etc). 

 
 
 

Altapure has a key role in rest homes - many to most deaths are not definitively diagnosed, swab tests miss 30-50% of actual COVID-19 cases, so 'terminal'  HLD of all vacated rooms is a good start - for both reality cross infection reduction, but also marketing perception by that facility of 'guaranteed ultra clean risk free rooms'.

And even more so in hospitals for theaters etc.

 

Then, and fortuitously for PPE reprocessing including especially N95 masks, which if not for resource issues, should be worn by all healthcare workers, but with Altapure there should be no resource issue.  

 

Long reply to a short question! 

My thoughts, Ben