My thinking about booster #2 has shifted a bit in the past few days. Here's a 🧵
First of all, on Tuesday I decided to mix-and-match: I got Moderna after 3 Pfizers. The side effects were similar as with my Pfizers – just mild arm ache. Some folks have worse, of course. (1/25)
When the evidence became clear last summer that booster #1 was needed, the general thinking was that it would deliver long-lasting protection. Why? Shots 1 & 2 had been given very close together (for good reasons), which didn’t give the immune system much time to mature. (2/25)
Ergo, a boost 6-8 months later would lead to long-lasting coverage…or so we thought. Perhaps we’d need a yearly booster (maybe combo w/ flu shot) but not more often than that.
So we were surprised that protection waned 4-6 mths after booster 1, leaving us now to ponder...(3/25)
…whether 2nd boost is needed. Until this week, a reasonable bet was that booster #2 would protect for 4-6 more months, matching #1.
But out comes a new Israeli study @NEJM showing booster #2 offers great (~3-fold) protection against SEVERE infection (ie hospitalization)...(4/25)
…for at least 2 months & maybe longer (the @NEJM study followed patients for only 6-8 weeks). But the good (2-fold) protection against SYMPTOMATIC infection appeared to by gone at 2 mths. nejm.org/doi/full/10.10…
This finding is a bit of a shocker & merits some rethinking.(5/25)
Let’s throw a couple of other factors into this confusing brew. First, I’m increasingly concerned about long-term effects of a Covid infection. Recently, we’ve seen convincing evidence that, on top of Long Covid symptoms, Covid infection is associated w/ ⬆long-term risk… (6/25)
There's substantial uncertainty around all these findings – particularly the degree to which vax may ⬇the risk (ie, is a breakthrough infection less likely to raise risk than infection in unvaxxed person), whether the risks are the same with an Omicron infection (vs. … (8/25)
…a prior variant), and if antiviral Rx makes a difference. But for now, as someone who has not had Covid (that I know of), I still believe that preventing a symptomatic infection is a worthy goal – even though I know my chances of dying of Covid (after 3 OR 4 shots) are… (9/25)
…quite low. The question: what am I willing to do to prevent symptomatic Covid? Am I willing to take a booster every 2-3 months? For me, probably yes, at least for a while – maybe until we have better boosters or a sure supply of Paxlovid or other effective antivirals,… (10/25)
… along w/ evidence they⬇Long Covid risks. To those who say that a shot every few mths to prevent a bad disease is impossible, I’d ask them to talk to someone w/ Type 1 diabetes, who takes shots daily. There’s the “immune exhaustion” argument (too many shots will cause…(11/25)
… the immune system to wear out), which is theoretical but may prove quite real. More study needed.
So based on what we now know, let’s think about both decisions I made this week when I got booster #2: 1) now vs. later, and 2) mix-and-match vs. stick with the same vax. (12/25)
Now or later: I’ve argued against trying to “time the market” – holding off on a shot now to try to time the period of max efficacy with a possible surge later in the year. But the short-lived efficacy of the 2nd booster shifts my thinking on this one, at least a little. (13/25)
For those @ low risk of a serious infection (eg, healthy 50-year-old), the argument to wait is stronger. As @DLeonhardt pointed out yesterday nytimes.com/2022/04/06/bri…, we’re still unsure why we’re NOT seeing a big BA.2-associated surge. But (notwithstanding a mild uptick…(14/25)
… in the Northeast & plenty of high-profile cases), Covid case rates remain low.
So, if I was on the “now or wait” fence last week, the new Israeli data would push me to “wait.” (For me, a 64-year-old w/ mild asthma, I’d still go w/ "now," but it would be a closer call.)(15/25)
Second, the question of mix-and-match. I chose to mix because of theoretical evidence that it provides broader immunologic coverage than using the same mRNA, & some real evidence that Moderna is a bit more effective than Pfizer. The Israeli data comes from people who got…(16/25)
… 4 Pfizers. I can’t prove a switch to Moderna would have led to longer efficacy, but it’s a possibility. So I’m glad I chose mix-and-match. (@ZekeEmanuel says he'd switch to J&J.)
Here too, if I were on the fence, the new data might push me to mix-and-match. And yes,… (17/25)
… – though now we’re in a data-free zone – I’d probably mix-and-match in the other direction too (get Pfizer after 3 Modernas), thinking the evidence supporting broader immunity from M-&-M trumps the minimally ⬆efficacy of Moderna. But now we’re truly hand-waving.(18/25)
The FDA advisory committee meeting yesterday spent a lot of time on re-jiggered boosters, particularly ones specifically targeted against Omicron. statnews.com/2022/04/06/tra… Bottom line: no evidence yet that they’ll be better or more long-lasting, & it’ll take at least…(19/25)
…6 months to sort it out. So if your reason to wait is that you’re holding out for a better booster, it won't come anytime soon & thus isn't a good reason to delay now. We should learn the answer in the Fall, and so it might influence a Booster #3 decision at that time. (20/25)
How about folks who had an Omicron breakthrough infection? I’d stick with my rec that someone who had Omicron after 3 shots should wait before getting a 2nd booster. I don’t think the Israeli data changes that equation, other than to make it more likely… (21/25)
… that the Omicron infection-related immunity may also wane a bit faster than we thought. So if I had a breakthru in Jan-Feb & was at reasonably high risk (>age 65, let’s say), I might be thinking about a booster in May-June; perhaps sooner if there are signs of a surge. (22/25)
How about masking? For those of us who don’t want to get Covid, consider your protection to be quite high for ~2 months after a 2nd booster or a booster plus breakthrough. By the time you’re in month 3-4, you should deem your level of protection to have dropped… (23/25)
…significantly, & masking decisions should be made accordingly – meaning that in areas w/ low case-rates (<10/100K/day), it’s fairly safe to go maskless indoors, but in areas of⬆transmission you should consider yourself pretty vulnerable 3 months after booster #2. Drat. (24/25)
Sorry – just when it seems like we can ditch the 3-dimensional chess set, things have gotten even more complex. But such is life in the Covid World.
I hope this is helpful as you make your own decisions in the face of significant uncertainty & rapidly evolving evidence. (25/end)
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Covid (@UCSF) Chronicles, Day 1371
I haven’t X'ed much about Covid lately, mostly because things are fairly stable. But a lot of folks have asked me what I’m doing, Covid-wise.
So today: how I’m acting, & why. Graphic below shows my general approach; more details follow. (1/25)
How am I acting currently? Given a moderate uptick in Covid over the past two months, I’m back to masking in crowded and poorly ventilated places, particularly when I don’t need to talk. When I do mask, I always use an N95; I see no reason to wear a less effective mask. (2/25)
Examples of where I currently mask: crowded stores, airplanes or trains; elevators; and theaters. But given that today’s uptick is only moderate, I’m still OK with indoor dining (though will opt for outdoor if conditions allow) and for going maskless at holiday parties. (3/25)
Covid (@UCSF) Chronicles, Day 1249
While good data are far harder to come by than in the past, it’s clear that we’re experiencing another Covid uptick. Today: what that means and how you might choose to alter your behavior in response. (1/25)
First, the evidence for the uptick (I don’t say “surge” since I associate that with the massive surges of the past):
This curve of hospitalizations (a reasonable proxy for the amount of Covid in the community) shows a definite, but relatively mild, upward trend. (2/25)
Alas, one can't look at any single measure to quantify an uptick anymore. But all arrows now point in the same direction: up (⬆ wastewater,⬆ hospitalizations,⬆ deaths,⬆test positivity). Even my fave measure, @UCSFHospitals’ asymptomatic test positivity rate, is no… (3/25)
Until this week, I remained a NoVid, which I chalked up to being fairly cautious, fully vaxxed & a bit lucky.
This week my luck ran out. My case is a cautionary tale, particularly for the “just a cold” folks. Mine definitely was not...I literally have scars to show for it. (1/22)
I’ve got my 2nd bivalent in April, so my protection against a severe case was still strong, but the 2-3 month window of protection vs. getting Covid had passed. I've let down my guard a bit: still masking on planes & in crowded rooms, but I do now eat and drink indoors. (2/22)
This week, I was on clinical duty @UCSFHospitals. We are still required to mask in patient areas (good!). I felt fine until Sunday afternoon when, after leaving the hospital, I noticed a dry cough. By Sunday night, I felt flu-ish, with a sore throat, fever, and chills. (3/22)
Covid (@UCSF) Chronicles, Day 1161
With the Pub Health Emergency over, it's a good time to update you on my view of Covid & my current approach to Covid behavior – which is now based on 2 principles: 1) Is the risk worth it? 2) Can I live w/ the behavior for the long haul? (1/25)
First, let’s review today's situation. Since Omicron's emergence in 11/21, the biggest surprise has been the absence of surprises. Yes, we’ve seen a few variants that led to mild surges, but we haven’t had to interrogate our Greek dictionary for a new letter for 18 months. (2/25)
mRNAs still work great in preventing severe infection, and Paxlovid, home tests, & ventilation still work well too. Long Covid remains a concern, but we know that both vax & Pax lower its frequency, that most (though definitely not all) folks… (3/25) jwatch.org/na55957/2023/0…
Important @TheLancet systematic review finds Covid infection confers robust & long-lasting (good at 40 weeks) protection vs both symptomatic & severe Covid infection.(Weaker w/ Omicron, but still good.) thelancet.com/journals/lance…
How will results influence my behavior/thinking?(1/7)
a) I've been considering a Covid infection to be the equivalent of a booster in terms of protection against reinfection & severe disease (hospitalization/death). These study results indicate that it is at least that good, maybe even a bit better... (2/7)
b) We've been headscratching about why XBB variant didn't cause more of a surge, despite low uptake of the bivalent booster. It may be that immunity from all those 2022 Omicron infections kept it at bay (that's informed speculation – Lancet study ended before XBB spike)... (3/7)
Covid (@UCSF) Chronicles, Day 1038
Some folks continue asking what I'm doing viz Covid behavior...
Answer: I'm changing my behavior. In the Bay Area, I'm now OK with indoor dining & removing my mask for small group gatherings.
I haven't changed, the risk has. Here's how: (1/25)
Specifically, I haven't changed my perspective on balancing prudent caution with everyone's (including my) desire for "normal."
But, in the Bay Area at least, the Covid risk has come down considerably, and, by my way of thinking, this allows for a more permissive approach.(2/25)
Where I'm coming from: 1) I'm 65 & haven't had Covid 2) I want to live as fully as I can, but am comfortable taking reasonable steps to avoid infection 3) I'm fully vaxxed & had bivalent in Sept 4) My main fear is Long Covid, which I peg at ~5% probability per Covid case. (3/25)