Coronavirus Emerging Science
Emerging science on Covid-19: 24th January 2021 update with Dr. Simon Collins
Previous articles in this series are archived here:
I use this blog to highlight the developments I think will be of most interest to patients. Since my last update (18th November 2020), vaccine arrival and roll-out has become the big story, along with new, more infectious variants of Covid. Here, I'll try to tie together where we're at as of today (24th January 2021), with the caveat that as new evidence emerges, things will continue to evolve. A snapshot as of now:
If you've had Covid already:
An important study from Public Health England (14th Jan. 2021) is showing that most recovered patients have immunity for at least five months (and probably longer). Even if they do become re-infected, they're unlikely to get seriously sick. They can, however, re-acquire the virus (without knowing) and pass it on again to others – so they must continue to use all the usual prevention measures.
The study conclusions are available here.
The new variants of Covid:
- UK variant (B.1.1.7)
- South Africa (501.V2)
- Brazil (B.1.1.248)
The UK variant is 50% more infectious – this alone will lead to more deaths. The UK variant might be more lethal on a case-by-case basis, but if it is, it's probably marginally rather than significantly moreso. It looks like both the Pfizer/BioNTech and Moderna vaccines work fine against it.
There might be some reduction in vaccine effectiveness against the other variants. Research from South Africa on a very small group of subjects (44) published on 19th January 2021 suggests that patients who have recovered from Covid might be vulnerable to being infected once again if exposed to the 501.V2 variant and that the mRNA vaccines might not work well against this variant (but it is likely that re-infection like this would not lead to serious illness).
Both of the mRNA vaccines (Pfizer/BioNTech and Moderna) are very effective (at least ideal, trial settings, where they were 95% effective – real-world experience may show, in the weeks ahead that they do or do not attain the same level of protection while being used in large scale settings e.g. in Israel).
Both vaccines lead to an antibody response in the patient that is superior to the protection you'd get by having had Covid infection itself.
There is serious debate about the merits of delaying the 2nd dose of either vaccine on purpose, as is occurring in Britain, and not giving the 2nd dose at day 21 (Pfizer/BioNTech) or day 28 (Moderna) but at a later date (e.g. at day 90). The advantage is the ability to vaccinate more people with a first dose at a time when vaccine supply is finite. The (for now) unknowable possible disadvantages are (a) increased 'no-shows' of patients 90 days later for a 2nd dose (which is important to ensure long-term protection and (b) possible inadequate coverage from one dose only 2 months after the first dose was given.
Both vaccines could be re-engineered within a matter of weeks, if necessary, to deal with Covid variants that might emerge in the future. On paper, it currently looks like it would take a few years for the Covid virus to mutate to the point that re-engineering of the vaccines would be necessary.
Upcoming vaccines: in late January/early to mid-February, data will emerge on the one-dose Johnson & Johnson/Janssen vaccine (which can be stored long-term at normal fridge temperature). While the company is about two months behind it's manufacturing target, so will be limited in the number of doses it can supply initially, data which were to show this vaccine worked well would make it a huge help in the drive to vaccinate large numbers of people.