A visual representation of what we know and don't know about waning immunity.
We know, at 6-8 months:
- Partial vax not great.
- Full vax ~70-85% effective (better vs severe disease than infection).
- Booster gives short-term bump.
We don't know what happens next.
4 scenarios:
Scenario A: Booster gives long-term benefit (by increasing immune memory), and immunity to 2-dose series continues to wane.
In this scenario, boosters are the right thing to do, now.
Scenario B: Booster doesn't improve immune memory, so the added effect of booster is short-lived.
This is the worst-case, and in my mind least likely - because vax has been effective, w/o booster, for 8 months now.
Here, booster helps a bit, but we need revised vax.
Scenario C: Booster improves memory response, but current vax continues to work well.
Booster here is helpful, but not immediately urgent. Since current vax remains effective, we have time to wait for more data.
I'm an optimist at heart, like to think this is most likely.
Scenario D: Two-shot series works well long-term, booster doesn't add much.
In this case, the effect of the booster is small and short-lived.
Meaning boosters aren't that useful, and if used, the best time to give booster is at the start of a surge.
Best policy?
A: Booster now
B: Prioritize revised vax
C: Booster non-urgently
D: No universal booster
In all cases, vax immunocompromised. And if someone wants booster, likely doesn't hurt.
But we don't know which (A-D) is true.
My take: far-reaching policy w/o data is risky.
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1b. This makes sense, because:
(a) in the US, people 65+ have the lowest case rates
(b) most of those cases are in not-fully-vax'd
(c) fully vax'd recover faster
(d) people 65+ have fewer contacts
Bottom line: to halt transmission, fully vax'd seniors would be lowest priority.
@NEJM joining the waning immunity debate. I'm going to push back a bit.
Data from @UCSDHealth of vax effectiveness in health workers: 94% in June, 65% in July. Interpreted as "likely to be due to...delta and waning immunity over time, compounded by end of masking requirements."
1. re: delta. ~50% of CA sequences were delta in June. So if delta were the driving factor, we would expect to see some waning of vax effect in June (~halfway between May & July) - which we don't.
2. Same thing with waning immunity. According to the paper, vaccination started in mid-Dec, and it took 3 months to get 76% of workers vax'd. Why then would we see no waning of effect in May or June - and then a sudden drop of 30% in July?
If you're in the US right now, how worried should you be about the recent uptick in COVID cases?
A plain-language thread below.
Long story short - the 4th wave is here, and it's time to start acting now before things get worse. But without hitting the panic button.
1. Let's start with the bad news.
Cases are doubling about every 9 days right now - nationwide. This is eerily similar to the rate of increase when each of the previous 3 waves hit. And no state is being spared.
In terms of case counts, the 4th wave is happening. Now.
2. COVID deaths are likely to follow.
We generally see a 3-week delay between when cases go up and when deaths increase.
Since cases have only been increasing for 3 weeks now, we haven't seen an increase in deaths - but we will soon.
I'm really struggling these days with the politicization of pandemic science.
A quick thread on why I worry that we as scientists are only being inclusive of certain perspectives.
And thereby pushing people away who might otherwise have a lot to offer.
Consider papers with one of the following conclusions:
COVID worsened disease X (except flu).
COVID worsened disparities.
Measures should be more stringent.
Things are going to get worse.
Conservative policies made things worse.
Then consider papers with opposite conclusions.
These conclusions all have political undertones.
But papers w certain conclusions are more likely to be published & cited, while others are more likely to be criticized.
So, if you are an intelligent, but conservative-leaning, thinker, is this a game you want to join?