Interesting. Looks like there might be some rationale for heterologous dosing, beyond just availability.
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Well, I guess I got that going for me. I just got the second booster ( 4th shot) on Tuesday. That puts me at 3 doses of Pfizer and one Moderna. Yay me.
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Iām 2 Pfizer, 1 Moderna, holding out for the 6G chip. 
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Thatās in addition to the time you caddied for the Dalai Lama? 
If the reference is to obtuse, holler. 
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2P and 2M for me after tomorrow.
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Merlot for meā¦no specific dosage 
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Let me think. I may have to ask the harmless squirrel and the friendly rabbit.
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I would have called first but there was no listing for Mr Wonderfulā¦
What spelling did you try?
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Ok. I guess as Iāve had 3 Pfizers, will go get a Moderna. Will wait until after seeing my MDs in a week. Iām 6+ months past September booster. I mostly can isolate and wear great masks.
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There was already evidence of the benefit of heterologous mRNA mixing of vaccines last year, and so I got a Pfizer booster after Moderna primary series last fall. What to do for this next one, though ā Moderna or Pfizer? Iām thinking another Pfizer, so I will be 2 and 2.
The best I recall, that study was based on full doses and only looked at disease prevention. It also found that M on top of P, was about the same as all M, so going heterologous with M primary didnāt seem to offer an advantage.
The interesting thing about this one is that it shows that each mRNA induces a different type of immunoglobulin response. The theory is that it would be sort of like hybrid vigor. It gives even stronger support for not only mixing, but boosting with Pfizer if one had Moderna primaries.
I havenāt kept up much though since my choice was already made. Maybe I missed other studies.
I posted this on the vaccine thread, here is a more recent study showing the differences between the two mRNA vaccines, and Eric Topolās twitter thread where he recommends mixing vaccines.
https://www.science.org/doi/10.1126/scitranslmed.abm2311
And Topol again on who should get a second booster:
Should I get a 2nd booster?
The deficiency in our knowledge base is the lack of follow-up, maximal at only 40 days so far, for enhanced protection vs severe illness, hospitalization and death. Surely thatās worth something, and likely will have some durability for a few months. but It probably will have faster attrition than BA.1 protection from the Israeli data weāve seen so far on infections. So this should be viewed as a temporizing, bridging measure.
I would recommend the 2nd booster if you are more than 4-6 months from your 3rd shot, you are age 50+, you tolerated the previous shots well, and you are concerned about the BA.2 wave where you live, or that itās getting legs as you are trying to decide. Or if you are traveling or have plans that would put you at increased risk.
It can certainly be deferred, but the question is when is the right time, and whether an Omicron-specific vaccine will have any advantage over a 2nd booster directed at the original strain. The data from 2 animal models (macaques and mouse models) suggests there may not be advantage of the Omicron-specific vaccine but that may not correlate with its effect in people. From my discussions with FDA, it is not likely the Omicron-specific vaccine will be available before late May or June. So you can factor that uncertain added benefit and timeline into your decision.
Itās also fine to wait if thereās a low level of circulating virus where you live and work. Israel will have more follow-up data soon, and for all age groups, so in the weeks ahead weāll know more about the magnitude, age range (such as age less than 50) and durability of the benefit.
If you had 3 shots and an Omicron breakthrough infection, thereās little need for getting a 2nd booster at this point. Youāve got some hybrid immunity and you can save an extra shot, if or when thereās ultimately supportive evidence for a later time.
If you havenāt had your 1st booster, youāre long overdue to get it. It was lifesaving vs Delta for people age 50+ and vital for maintaining high level of protection vs severe disease from the Omicron family of variants.
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Hereās one description of the study: https://twitter.com/drericding/status/1451418802416197633?lang=en
As a Moderna primary series recipient, it was intriguing that me that the lower-dose Pfizer booster produced more antibodies than the full-dose Moderna (study was done with full-dose Moderna) for those who got Moderna as their primary series. So that is one of the reasons I chose Pfizer for my booster. And I was certainly interested in disease prevention (still am). The rest of the results didnāt seem that useful, since they werenāt using the half dose of Moderna that became the booster dose.
Theyāll be good reads. I was already boosted before either came out, so I missed them. Guess I made the right choice. 
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This thread is a nice summary of what research has found re: effects of Covid on the brain. Each powerpoint contains a lot of information, much medical jargon but shows in the end the evidence suggesting long term effects such as Parkinsonās, MS, psychiatric diseases that may be a direct result of Covid.
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So adding a nucleocapsid vaccine to a spike vaccine may be helpful. Is availability in the works?
Did I miss this: was this Delta, Omicron, other or all?
How do treatments like monoclonal antibodies and the Pfizer pill affect this damage? Steroids and anticoagulants?
This stuff scares me, My family has seen what damage viruses combined with autoimmunity can do.
Sedation on a ventilator also has cognitive and motor effects, but the fact that some minor cases result in neuro or cognitive issues is certainly concerning.
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Got my second booster today. Opted for Pfizer after going all Moderna, for all the reasons upthread and also the hope that I might have a milder reaction.
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You can go to Mexico and see if you can find an inactivated whole virus vaccine there (Bharat Biotech, Sinopharm, and Sinovac are approved there). The inactivated whole virus will have nucleocapsid as well as spike proteins in it. Mexico ā COVID19 Vaccine Tracker
But note that antibody tests for the nucleocapsid antibody that are commonly used to check for prior infection with the real virus will no longer make that distinction after you get an inactivated whole virus vaccine.
They werenāt approved here because they were less effective. There is some thought that something like Covaxin or Sinovac on top of mRNA might be useful for just that reason, more antigens, and thus harder to get escape.
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There was a study that came out March 29th on mixing and matching - noted benefits.
Hereās a Q&A around the 4th dose from epidemiologist Katelyn Jetelina.
I just got my parents (78, 80 years old) appointments for a Moderna booster this week, as they had three Pfizers with the most recent at the end of September.
Iām 48, and have asthma; I had my first two as Pfizer, and the half dose of Moderna at the end of November (based on what was known then about mix and match, although the half dose wasnāt a part of that!) - Iām hoping that more research will be coming in towards the fall around protection and subsequent boosters.
(edit: I didnāt insert the hyperlink to āresearchā in the last paragraph; that was added by CC and not worth clicking).
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