Thread by @MartinJuhl2

Collection of input to the discussion on:
➡️Two doses 3-4 weeks apart (per protocol)
vs
➡️Delay 2nd dose of up to 3 months

As with everything regarding this pandemic, there are no easy solutions, only difficult compromises.
1/x
@henrik_ullum @Heunicke @stinuslindgreen

Pfizer/BioBTech Protocol here

2nd dose is provided after 21 days & readout was 7 days after 2nd dose
pfe-pfizercom-d8-prod.s3.amazonaws.com/2020-09/C45910…
2/x

Moderna dosing & schedule

The Moderna COVID-19 Vaccine is administered intramuscularly as a series of two doses (0.5
mL each) 1 month apart

fda.gov/media/144637/d…
3/x

Astra-Zeneca/Oxford vaccine. The 2 doses are administrated 28 days apart
thelancet.com/journals/lance…

They do have subgroup data on 3 months dosing interval

https://twitter.com/matthewherper/status/1344307748427739136?s=20

UK delaying 2nd dose of AZ/Oxford vaccine

https://twitter.com/michaelmina_lab/status/1344196883024142336?s=20

4/x

The discussion to potentially wait with the 2nd dose, is to increase the number of individuals, who are vaccinated with 1 dose, thus slowing the spread of the virus. Especially, in light of the concerning new data on mutated variant B.1.1.7/N501Y

https://twitter.com/MartinJuhl2/status/1344547704723148802?s=20

5/x

Arguments for delaying 2nd dose

https://twitter.com/Bob_Wachter/status/1344667655324585986?s=20

6/x

"I am still a proponent of 2 dose vaccine but given the urgency, we can delay the 2nd dose until more vaccines become available. I know many others have been saying this all along, but it was the B.1.1.7 variant transmission rate that did it for me."
7/x

https://twitter.com/VirusesImmunity/status/1345086669607890945?s=20

Below is a real risk highlighted, in regards to delaying 2nd dose.

8/x

https://twitter.com/EckerleIsabella/status/1345024694643208195?s=20

"'Partial immunisation', caused by a delay of the second vaccine dose could accelerate the emergence of such 'vaccine-escape' mutants."
9/x

https://twitter.com/BallouxFrancois/status/1345395237666119680?s=20

"These concerns might work out OK. But they might not. We simply *do not know*, and human immunology is very much capable of dealing us either high cards or low ones here. It’s a gamble. No other word for it."
10/x

https://twitter.com/Dereklowe/status/1344644935186833414?s=20

Overall, there seems to be a high risk associated with changing the dosing regiment, as increasing the rate of escape mutations, potentially lose vaccine efficacy, would be a bad start to 21. On the other hand, fast vaccine rollout might be the best way to control the spread
11/x

I have tried to collect input on the subject for decision makers to have easy access to top-experts opinions on this difficult subject.
/end

Follow up #1
More caution on delaying the second dose, from someone with has on experience on developing viral escape mutations

https://twitter.com/florian_krammer/status/1345791187236646912