Thread by @ashishkjha

New @TheLancet study on Oxford Adenovirus vaccine out and is indeed good news

First, its an early phase trial -- assessing both safety and efficacy

Randomized -- about 500 folks in each arm

Its good news -- but we have to not over-state things

Thread

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The vaccine uses a chimp adenovirus vector with the SARS-CoV2 spike protein (which SARS-CoV2 uses to enter into human cells)

First, safety data:

Most folks with vaccine (67%) had pain at injection site, fatigue (70%) headaches (68%). All short-lived, improved with tylenol

2/5

safety (contd):

No severe reactions in the active vaccine group.

Efficacy -- did vaccine elicit an immune response?

First, a primer:

There are two main arms of immune system: humoral (antibodies) and cellular (T-cells)

Immune system more complicated but lets be simple

3/n

Efficacy (immune response) continued:

1. Everyone (by the second dose) got neutralizing antibodies -- this is good news

2. Most folks formed a cellular response against the spike protein.

Immune response looked durable at least out to about 6 weeks

4/n

Summary:

Vaccine appears safe in the short run, elicits a robust immune response.

Great

So what do we NOT know (yet)??

First, whether vaccine is safe in longer run

Second, whether it actually prevents infections or at least severe infections (that's the point, right?)

5/6

So on to phase 3

Large trial with a much longer follow up for safety

And need to know if vaccines prevents (severe) infections

Need to test in kids, older folks

I'm very optimistic about vaccines in early 2021.

Until then, we have to protect as many lives as possible.

Fin