Thread by @Bob_Wachter

1/ Covid (@UCSF) Chronicles, Day 259

The vaccine news remains astoundingly positive. Reacting to my upbeat mood, a reporter asked me if there’s anything that keeps me up at night. Aside from the cataclysmic current state of Covid (likely to get worse, I fear), there are a few:

2/ First, the question of who gets the vaccine first is tricky. (Breaking news: @CDCgov panel just weighed in: tinyurl.com/y53atcys, and I agree.)

One can make a case for many groups to be first in line: healthcare workers; people >65 in nursing homes; essential workers…

3/ …(like food handlers, police, firefighters, & teachers); and people at high risk for bad outcomes (people over 65 and those w/ preexisting conditions). One can make an argument for all of them to get vaccinated as soon as possible. Alas, we quickly run into a math problem…

4/ …Namely, there won’t be enough vaccine for all these groups until spring. Thanks to @AriadneLabs, which did the legwork of removing duplicates (people who fit in multiple categories) to estimate the number of people in each of the possible Phase 1 groups. They add up to 144M.

5/ And here’s my estimate of how many people in U.S. can be vaccinated at various times in 2021. It’s based on statements made by @Pfizer, @moderna_tx & Op Warp Speed, and assumes we have enough vaccine to vaccinate 20M by Jan 2021, 150M by June, & the entire country by December.

6/ As the graph shows, I estimate it’ll be ~May before we get to all 144M of the high-priority folks. This timeline could shorten if additional vaccines are approved, and lengthen if there are rollout glitches. If demand is low, I assume we’ll just broaden the eligible groups.

7/ We'll see how people react to the draft CDC priority list. I’m concerned these decisions will be contentious and – this being Covid – politicized, since it will raise matters of race, homelessness, incarceration, elders, healthcare workers...in other words, myriad hot buttons.

8/ Herd immunity, which we should reach at ~70% vaccination, isn’t a magic on-off switch: as we close in on it, there will be fewer cases & fewer severe cases, since there'll be fewer people vulnerable to virus & fewer who'll get very sick if they do get Covid. So, even though…

9/ …we might not reach 70% protected until Sept., the impact of widespread vaccination will be felt before that. Also, there are tens of millions who are already immune via prior infection (and millions more each week, sadly), which will shorten the path to herd immunity a bit.

10/ Second issue that keeps me awake is the shot itself. We know that a fair # of folks will have symptoms – arm pain, fever, the blahs – that’ll last for 1-2 days. Seems a small price to pay for immunity to a terrible infection. But will this day of discomfort dissuade people…

11/ …from getting their shots? Probably some, particularly in lower-risk groups – & we’ll need many to take shots to get to herd immunity. Analogous to the challenge of getting low-risk folks to wear masks & buy health insurance – many are too selfish to accept pain for others.

12/ There will also be post-vaccination issues: when somebody has a post-vaccine fever, do we assume it’s the vaccine? Test for Covid if it lasts for >2 days? Should healthcare or essential workers come to work if they feel sick after their shot? We’ll need super-clear guidance.

13/ 3rd concern: misinformation. Below: if we vaccinate 10M Americans, how many will develop a serious illness in 2 months after they got their shots. Answer: many thousands (& I’ve only included 4 illnesses, plus death).

And the vaccines will have zero to do with any of them.

14/ Whether it’s anti-vaxxers or Russian bots, if somebody wants to turn every post-vaccine illness into a “See, I warned you” canard, there’ll be ample fodder. We’ll need a strong campaign to combat it, ie this tinyurl.com/y5ym92c5 Nothing I’ve seen in 2020 reassures me here.

15/ I also worry about next 6 mths – will folks let their guards down because vaccines are coming? That would be a terrible mistake – while vaccines will protect the recipients, they’ll do little to protect others in the community until we reach herd immunity levels next summer.

16/ Other worries: reviewing Biden’s appointees, from Covid task force to chief of staff Ron Klain, I have great confidence in their ability to pull off the logistics effectively, safely, & with minimum drama. But the first month of distribution will be done by Trump's team…

17/ … and, while they’ve managed Operation Warp Speed well, the Trumpers seem poised to throw monkey-wrenches into the handoffs. I doubt this will screw the whole thing up, but even a few weeks’ delay will lead to millions of preventable cases & thousands of preventable deaths.

18/ I worry about the impact of approved vaccines on ongoing trials. If we can get EUA’s for Pfizer, Moderna & Astra Zeneca, that’s probably a deep enough bench to vaccinate everybody in the U.S. But more would be better, particularly as we think about the vast worldwide needs.

19/ It’s going to get tougher to do placebo-controlled vaccine trials.(Is it ethical to randomize to placebo once 95% effective vaccines are available?). We may be forced to evaluate new vaccine candidates based on their similarities to ones we know work, which is a bit dicey.

20/ I worry about kids, since we haven’t even begun to test vaccines in them. But if we can reach herd immunity by vaccinating everybody else (incl. teachers), we may not need to obsess about reaching kids, particularly the youngest ones (who are at low risk for illness/spread).

21/ As I’ve said, while I do worry about uptake, I don’t worry too much. Unlike childhood vaccines, many people know friends & family who were sickened or died from Covid, & everybody wants their lives back. I’ll bet that uptake is going to be quite high, esp. in hi-risk groups.

22/ I do worry about keeping track of who got which vaccine. Who will remind a pt to come in for a 2nd dose, and be sure that the 2nd dose is the same brand as the first? If we had a national medical record (like the VA or the NHS), this would be easy. But in the U.S., it’s not.

23/ I worry a bit about how long immunity lasts, but also not too much. We’re now pretty confident that immunity lasts for >1 yr. If it turns out that we need a booster in 2-3 years, that'll be a small price to pay to save tens of thousands of lives and a return to normal life.

24/ So, yes, I do have worries. But let’s not lose sight of the fact that, on November 1st, we didn’t know for sure that we would have ANY effective vaccines. Today we have at least 2-3 highly effective ones, an impressive safety track record, and millions of doses ready to go.

25/ So yes I have worries, but the light at the end of the tunnel is increasingly bright. We just need to get there.

How confident am I? First, I’ll get my shot the day I’m eligible. And I just booked a golf trip in Sept. Perhaps living dangerously, I didn’t ask about refunds.