The latest vaccine in the US is for KP.2 (Moderna or Pfizer) or JN.1 (Novavax), but XEC is a descendant of JN.1 and is a lot closer to JN.1 and KP.2 than it is to XBB.1.5 that the prior year vaccine targeted.
So it is not a surprise that someone who recently got a vaccine close to the current virus avoided the sickness that infected those who may have had an old vaccine a year ago.
I got the Novavax (along with the flu shot) a few days ago, and am happy to report that I got nothing more than a sore arm and 24 hours of mild fatigue. This is my first time with Novavax. Previously I have had Pfizer or Moderna, and always suffer through 24 hours of fever, chills and body aches. My husband and D25 also did great.
Oddly, I only had sore arm for all except one COVID-19 vaccine (2x Janssen, 4x Moderna). The one that gave a not-feeling-well for a day was last yearās Moderna XBB.1.5 vaccine.
Novavax does appear to have a lower rate of the unwanted fatigue, fever, chills, etc. type of effects.
I got my flu and Covid shots 2 weeks ago and it is the first time I have not gotten sick (other than the very first shot) out 6 shots. All 6 of mine have been Pfizer.
FWIW I fell down the expired test research hole a few months back when my kids had Covid and all we had were (very) expired tests (past all extension dates)- there is a tiny amount of research out there that suggests they may still be accurate even after a year past the expiration date.
Anecdotally, that turned out to be the case for us - we tested the expired ones right along with (newly purchased) āfreshā tests and got the same results - both positive and negative.
Not that Iād want to rely only on expired tests or if it was an urgent situation, but it was helpful to know that they may still be useful, particularly in terms of wanting to avoid the waste that all the unused expired tests in the trash are surely creating. 
We were able to get Pfizer and Moderna shots. This time around, we were happy to get the Novavax shot, which was a change for us and we hope it may provide additional protection.
Regarding expired tests, I once gave some that were close to the (extended) expiration date to some relatives who got COVID-19. Some worked, but some did not (no C line).
Someone mentioned that it is the liquid that eventually goes bad, but when that happens, the C line does not appear.
There are now home tests in the US that are combination COVID-19, flu A, and flu B (but not RSV). But they seem to be around $11-15 each.
A new study is out showing heightened cardiovascular risk in some patients up to 3 years post-infection. (many other types of bacterial or viral infections increase CV risk post-infection, but typically only for a short time)
Full study here:
https://www.ahajournals.org/doi/10.1161/ATVBAHA.124.321001
I have been trying to access info on the Novavax option and the articles I have seen indicate studies are ongoing, but effectiveness is the same as the mRNA shots, and possibly lower myocarditis risk (Mainly a concern for young men). Side effects may be lower.
Curious what led some of you to do the Novavax this time. I have mixed Pfizer and Moderna. I participated in a Johns Hopkins trial on how long antibodies lasted- about three months for significant levels for me.
I lot novavax last fall and will get that vax again this weekend.
No science in teh decision.
I took the Novavax because we had only had mRNA vaxes before and this one isnāt and I read something ages ago that perhaps you get different protections from a non mRNA vax. Iām all about trying to get the most and best protections we can. The vax didnāt hurt or cause side effects for me more Hāhe often feels a bit lousy for 48 hours after shots.
Back then, the ānon mRNA vaxā was the (now discontinued) Janssen vaccine (Ad26 viral vector) that gave a smaller antibody response, but a more robust T-cell response, compared to mRNA vaccines. The T-cell response is the second line of defense (versus antibodies that are the first line of defense), but appear to be longer lasting and more effective against variants other than the specific one in the vaccine.
Well, no idea if Novavax may do something similar. Other than that, no reason for getting Novavax.
So does Novavax have a similar effect on the T-cell response, that the Janssen shot had?
This article suggests there may be some t-cell production & protection.
Would love to know and understand more.
Here are some research papers comparing different COVID-19 vaccines. Note that, for the original doses, the Moderna vaccine had twice as much mRNA per dose as subsequent boosters, and the Janssen vaccine was one dose versus two for the others.
https://www.cell.com/cell/fulltext/S0092-8674(22)00653-5
https://www.nejm.org/doi/full/10.1056/NEJMra2206573
Here is one about mixing and matching the initial two doses of vaccine. Note that this study used the AstraZeneca vaccine instead of the Janssen vaccine. The AstraZeneca vaccine is a viral vector similar in concept to the Janssen vaccine, but uses a different vector virus and is supposed to be a two dose vaccine.
@ucbalumnus this is Janssen .
A differentiating feature of Ad26.COV2.S immunization was a high frequency of CXCR3+ memory B cells.
Wonder if this holds true for Novavax. I guess Iāll so some searches but there may not be studies.
For last fallās vaccine, I was on a bone med injection that may have reduced B cell immunity. This time I am not. I had COVID in October, a month after vaccine, and was in the hospital. I might not have had the usual B cell immunity from infection either.
As I remember I had antibodies tested for the Johns Hopkins study at 2 weeks, one month, three months and six months. Antibodies went down fairly quickly.
There have been many Novavax studies that discuss itās mechanism of action.
Most of that info is accessible from this page, but in summary:
Studies have shown that Novavax COVIDā19 Vaccine, Adjuvanted elicits an immune response, inducing both antibody-producing B-cells and multi-functional CD4+ and CD8+ T-cells. When challenged with the real virus, the antibodies block SARS-CoV-2 binding to the ACE receptor. Multifunctional T-cells produce multiple cytokines and are associated with an enhanced immune response to clear the virus. And effector memory T-cells target infected cells.
Hereās the full product insert:
I can add my weirdo bodily reactions to covid. I got the latest vax 2 weeks before our 12 day europe trip. 3 days before the end I had a bit of extra PND that didnāt go away with Benedryl, but did with DayQuil. I had no fever, cough, no congestion, and my HR was still in the 50s. Last time with covid it was 100-120 for 3 days. Next morning just slightly achy, but again everything went away with DayQuil. Figured it was some minor bug and kept trucking.
Day 4 I decided to test even though my symptoms were the same. Why? Because also each day I had a weird rash. First day it was in my elbows. I often get heat rash there and it went away with benedryl and hydrocortisone so I thought it was a reaction to the soap. Next day it popped up on my armpit. Went away with Benedryl. Next day, elbows. Day 4 it was on the top of my wrist and hand.
I knew covid can mess with my immune system and thought maybe it was covid? Tested and bright pink line. My PND and achiness went away the next day. The weird once a day rash spread out to 36 hours and then went away.
And H who was joined at the hip to me the whole time with no mask for either of us. Nada.
But then over the last couple of weeks Iāve been getting eczema on my eyes and lips again. I never had that before my first bout with covid. And then I struggled with it for about 9-12 months. But itās been gone for the last 8 or so!!! So Iām guessing it was covid that caused it the first time and not peri-menopause.
This is interesting to me. I know a woman who suffers terribly with fibromyalgia and she finally got some relief with low-dose Naltrexone.
