Covid-19 Ziņojums TLPA 2021.g.01.jūnijā.
This has been a hectic time for following the world’s progress re Covid-19. Vaccinations have started to become ever more widespread in many areas of the world, yet distressingly absent in other areas.
Assessing the mountains of data pouring into the media daily can seem bewilderingly overwhelming. To get a sense of what is going on,we must look at things as they change, and not focus on any one single data point. Much like viewing a movie – a single frame gives you some information, but the more frames you see in succession, the better an idea you get for what is going on. I shall try to simplify it a bit with this overview. The main thing is not to get bogged down in details, but rather look at the big picture trends as they evolve.
Beware of comparing one country’s numbers with another’s – compare one country’s numbers with itself only, because of variances in reporting philosophies and definitions of recoveries as well as the timing of such announcements. Nevertheless, the trends should be internally consistent and relatively accurate
First of all, looking at “active cases/million” gives you a current estimate of the viral activity at this moment. This data is probably not entirely accurate day-to-day because of variability in declaring recoveries. Following the reported active case trend over time indicates whether the active viral caseload is improving or worsening.
Active cases/million: LV slightly down
USA recently plateaued after down x weeks
UK up x 11 days after weeks of down
Good news – over the past several weeks, the number of countries worldwide showing significant improvememnts in active cases per million has steadily improved, approaching a 2:1 ratio (of better vs worse).
Herd Immunity from Covid-19
- if enough people have acquired immunity by way of natural infection or vaccination, the epidemic will die out because of a general lack of people left to infect. What is that %?
- a new virus, with no past history : recent thoughts : 75-85% (but! for measles -> 95%!)
- therefore, >75% need to be immune by previous infection or full vaccination
- reported cases per 100 people: global 2.2; LV 7.1 Can 3.6 USA 10.2 : thus, 5 seems a reasonable average to guesstimate for natural post-infection immunity
- If 5 people per 100 are presumed immune via prior infection, that leaves at least 70 more (per 100) who need to be fully vaccinated, or > 140 vaccination doses per 100 people, to approach herd immunity
To assess whether we are close to herd immunity, we can simply look at the number of vaccine doses administered per 100 people:
Doses per 100 people (as of 28.May.2021) :
- Worldwide : 24
- Top spot is UAE at 128; then Israel at 117;
- followed by Aruba (106); Bahrain (101); Malta (99); Chile (95); Curacao (94).
- UK is 8th at 94; USA is 11th at 88; Canada is 19th at 59; Latvia is 50th at 35; Iran is at 3.8; Egypt is at 2.1; South Africa is at 1.2; Vietnam is at 1.1….
If we relax precautions prematurely, we risk backsliding into another wave. Eg.: UK has started to increase its active case numbers, the USA has stopped its rapid improvement, even Israel has slowed its spectacular improvement….
No single country is homogeneous in its covid penetration – there are hot spots and safe areas everywhere, so until there is widespread herd immunity, we still must observe precautions, lest we allow another wave to establish itself.
Fully vaccinated people are probably quite safe, but all others are still at high risk and should continue to observe all precautions even as restrictions are relaxed, until they have been fully vaccinated or the pandemic is over.
No vaccine is 100% protective, and the possibility of silently/asymptomatically harbouring the virus in one’s nose/throat still exists.
How close can we safely get to strangers?
- Think of them as if they were chain smokers, continuously exhaling potentially virus laden clouds of smoke – you don’t want to inhale any of that (viral) smoke. The better the air movement, the less concentrated the smoke. But it still lingers in a room well after the smoker has left. Use that as a generalized guideline when assessing situations.
When can restrictions be safely lifted?
- This should be ideally done region by region, while the population avoids unnecessary travel
- Think of the pandemic as a raging conflagration – we must fight it aggressively until the fire is out, if we let up when the flames start dying down, we are seriously risking a flareup. Covid has shown, on multiple occasions, that it is fully capable of a flareup when restrictions are lifted prematurely. Prematurely, for Covid-19, really probably refers to “before herd immunity”….
- Assess covid activity by observing the ongoing change in active cases/million
- Assess herd immunity by looking at vaccination doses per 100 people (should be >140 doses/100 people)
- Always mask indoors and in areas where strangers are/have been (don’t trust anybody)
- Gradually loosen your own personal restrictions only after the pandemic fire is out (not just improving locally)
How do we stay safe? (outside of one’s own home)
– Precautions : masks, distancing, hand washing, good ventilation/air movement, vaccination, (un)common sense. Always wear masks when near strangers.
– “safe” distance? Even if masked, probably 2-3 metres
– “safe” exposure time? Probably several minutes (cumulatively), even if masked
– Minimize unnecessary travel to prevent inadvertent spread or import of virus from elsewhere (even if you are fully vaccinated!).
– Avoid crowds or large gatherings, especially indoors.
– Ideally stay mobile around strangers (masked or unmasked)
Those who have been fully vaccinated are probably quite well (but not necessarily 100%) protected against Covid, but they still should be very cautious when in close contact with strangers.
Andris Rubenis MD