Boosters.

A focused letter for tonight's consideration.

Aware [commentary on key news]

I’m going to dive in with my take on second boosters, as I’ve been getting lots of questions!

Sure. You might as well get one if you are eligible (over age 50, >4 months out from your last booster, immuno-compromised, etc.).

You have probably already heard of the 2 studies out of Israel showing some clear benefit from a 4th shot, particularly in those people over age 60. Out of a sample of 1,138,681 Israelis in this age group, a fourth dose reduced the rate of infection by 2 times and reduced the rate of severe disease by 4 times. Less infection equals less spread equals less long Covid. Here’s a nice visual:

Vaccination against Covid is a safety belt. It does not prevent all crashes, but reduces the damage and death. But a 4th booster has been shown to actually reduce infections by about 50%, for at least 30 days. More data coming.

If you are among the half of Americans who had Omicron (and it was confirmed with testing), and you were vaxxed and boosted before getting sick, then you now have hybrid immunity. Many studies have shown this is quite good, akin to a 4th shot for probably 6-12 months. Although the FDA and CDC do not formally acknowledge this hybrid immunity when making recommendations, a 4th shot in this situation is much less important.

Waiting for an Omicron-specific booster should be considered, but the reality is that these shots will not be available until late May or June most likely. And two studies in non-human primates showed no real advantage from the Omicron-specific boosters when compared to what we have available now. However, this may or may not hold true for human studies still being done.

Then there is the concern about over-training the immune system to recognize the original virus by getting the same shot 3-4 times. This issue remains up for debate. The NEJM ran an Op-Ed on this Wednesday. I have followed it pretty closely, so instead of getting caught in the weeds I will just say that the sum of evidence right now points away from the immune system getting too narrowly trained. We kind of saw this in real life when the new Omicron variant tested our strategy - boosters held up best, full vaccination second best, and previous infection brought up the rear. Had the worriers about over-training the immune system on the original shots prevailed, many more people would have suffered.

And current prevalence rates might provide some additional perspective about getting a 4th shot.

Covid case rates are much higher than you might think right now. The new BA.2 variant and sublineages are super-contagious, basically approaching measles. The good news is that with so many people vaccinated, boosted, and previously infected with Omicron, we are not seeing a huge BA.2 wave like some countries. But hospitalizations are still up 4 fold in our system over the past week.

I do realize how out of touch with the general public sentiment I have become whenever I walk into a crowded store full of people without masks. Or when I question the person I’m seeing in the office who is coughing and looking sick without a care. But I fear the seniors, immunocompromised, and unlucky among us can and will continue to pay a cost for our collective laxity.

Covid case rates reported in the paper and elsewhere are no longer a valid measure of community transmission. This is because more people are testing at home, which does not get reported. Many are having mild to moderate symptoms and not bothering to test. And there is now less coverage for testing the uninsured.

A more accurate metric seems to be the percentage of tests coming back positive. The higher the test positivity rate (TPR), the more we can extrapolate as to what’s actually going on out there. Also watch the trends - up or down - but don’t necessarily believe the absolute numbers.

It is currently estimated that only 7% of cases are being detected and reported in the U.S. That’s right, seven percent. And so if you are like me, with several friends and family infected recently, you know the rates are much higher than what we think. Reconsider your layers of protection right now. Rates are probably over 10x what is being captured and reported. Getting sick still sucks, long Covid is always a possibility, and the vulnerable people among us still need our help.

And talk to your doctor about antiviral treatment if you are feeling sick.

Boosters have been the biggest question in the office this week. We have been giving a lot of Pfizer shots. I think this demand also bodes well for blunting the current, less traceable wave. Unless the pandemic forces the issue, the next letter will be about a non-Covid topic… but I hope this quick update before Easter and Spring break helps.

Should I get the second booster?

Sure :)

Chocolate bunnies holding vaccines.