Emerging science on Covid-19: 3rd October 2020 update Q&A with Dr. Simon Collins
I hope the following is a helpful summary for patients. Much of it is drawn from the Journal of the American Medical Association (JAMA) and from interviews given by the inspiring Dr. Anthony Fauci, the director of the U.S. National Institute of Allergy & Infectious Disease.
In our previous discussion (19th July 2020, archived here), you said there were three big questions you wanted answered for
patients who receive a positive Covid-19 antibody blood test:
Clear answers have not emerged yet. With the passage of time, there is increasing evidence that the vast majority of previously infected people are not being re-infected within at least a six-month period. There isn't a lot extra of use to add to that statement yet.
We also talked last time about how reliable the Abbott antibody blood test was or was not for detecting infections as far back as November 2019 and whether the test would stay positive over time.
Where are we with that?
I don't have a definitive answer yet but I can give you two things to hold on to for now:
- I have asked the test's manufacturer, Abbott, for a clear answer. On 25th August they replied that while they will answer the question for me "any official communication due to the nature of the approval process may take months."
- The long-term persistence of the IgG antibody that is tested for with the test is shown in the graph in the 2nd page of this journal article (PDF Document). I have no evidence yet of 'positive' patients subsequently turning 'negative' and no evidence of the test becoming less reliable with the passage of time at detecting infections that occurred last March.
How do we get out of the Covid mess?
Beyond the prevention measures we're all trying to follow currently, the solution is a vaccine or a number of vaccines. The treatments you hear about (monoclonal antibodies, convalescent plasma, Remdesivier, Dexamthasone...) are a help but no substitute for an effective vaccine.
What's the bottom line with vaccine development currently?
Good, basically. The trials of the leading candidate vaccines are showing that the vaccines are inducing a level of neutralising antibodies that are as good as if not better than the levels found in the plasma of recovered patients. This is a very good sign. This is what the current cautious optimism is based on.
A number of vaccines have moved from animal trials to Phase I (30 patients approx.), Phase II (300 patients approx.) and now Phase III (30,000 patient approx.) trials. Phase III results for several vaccines are likely to be available between mid-November and mid-December. The emergence of a 2nd wave of infections is ironically good news for those conducting the vaccine trials – it will make it apparent more quickly if vaccinated volunteers are being successfully protected compared to non-vaccinated 'controls'.
The candidate vaccines have to be proven to be safe as well as effective before they get authorised. One leading candidate vaccine (Astra Zeneca) has had the U.S. part of its trial paused (not stopped or abandoned, though) due to a safety query.
What are the most advanced candidate vaccines whose trials are still proceeding?
Moderna (30,000 volunteers, Phase III started 22nd July), Pfizer (44,000 volunteers, Phase III started 22nd July), Johnson & Johnson/Janssen (60,000 volunteers, Phase III started around 20th September), Novavax (Phase III starting this month).
How many shots will patients receive?
Two doses, one month apart in most cases. The Johnson & Johnson vaccine is a single dose.
How effective will the vaccines be?
Be prepared for an effectiveness of 50% to 75%. There will be more than one vaccine used and it may well be that vaccine X gets used more in older people and vaccine Y gets used in the young, while vaccine Z gets prioritised for the Developing World because it does not have to be stored at such low temperatures as vaccine X or Y.
2nd generation vaccines may well come along in 2022 and make the initial brands look outdated, much as 5G mobile networks have replaced 3G and are replacing 4G. For now, a 60% effective vaccine that protected for at least 12 – 18 months would do!
Finally, what is your prediction for the speed of vaccine roll-out?
The initial successful vaccine may well be in use as early as January 2021 but much of the world needs to be vaccinated, so the roll-out will be gradual. Highest-priority groups get vaccinated first. It will take all of 2021 and much of 2022 to both manufacture enough doses and to then vaccinate everyone (and possibly vaccinate them twice, with a month between the doses).