I'm eligible for the 2nd COVID-19 booster shot, but have debated getting it now versus waiting a month or two. From what I've read, for people without risk factors, there's no urgency in getting it, and there may be benefits to waiting. (In case there's another big surge several months from now, or in case they come out with new boosters/vaccines based on the latest variants.)

In my area, the current case/hospitalization rates are very low, as low as they were in the very early days of the pandemic.

In two articles, I read something like the following, which I was curious about:

How Long Does It Take for the COVID Booster to Be Effective? (2021/12/21)

There's one other factor that can impact the effectiveness of a booster: time between doses. According to Penaloza-MacMaster, the longer the interval between your original vaccine series and the booster dose, the better antibodies your memory cells can create.

Why would the memory cells work better with a longer interval? So I tried to find an answer (I don't believe I did), and more info on these memory cells...


What to know about booster shots and third doses of the COVID-19 vaccine (2021/12/22)

COVID-19 vaccines create high levels of antibodies that can block the virus from ever infecting our cells. As time passes after your vaccination, however, you also develop memory B cells and T cell immunity and antibody levels go down. With fewer blocking antibodies, the virus might be able to start an infection. As viruses evolve, strains that can bypass those antibodies have an advantage and some people have such a high-level exposure that it can overwhelm the antibodies they do have. When this happens, we call it a “breakthrough infection,” but memory B cells and T cells are able to respond quickly and stop the infection before too much damage is done.

Breakthroughs, Boosters, and B cells … Oh My! (2021/10/12)

Over time, as the infection resolves and these antibodies fail to find virus, they will diminish in number. However, what doesn’t go away are the cells that can produce antibodies against the infecting virus. They are called memory B cells. We also have memory T cells that remain after an infection. If we are exposed to the same virus again, those B and T cells will recognize it and become activated.

The memory B cells will change into another type of B cell, called a plasma cell, and quickly start producing large quantities of antibodies. The antibodies produced by these cells are significantly more effective at stopping the virus than antibodies produced during the first encounter with a virus.

Activated memory T cells will cause the production of chemicals critical to our immune response, called cytokines.

This page has a nice simple chart:
Viral Attack: Memory Cells

Toward the end of each battle to stop an infection, some T-cells and B-cells turn into Memory T-cells and Memory B-cells. As you would expect from their names, these cells remember the virus or bacteria they just fought. These cells live in the body for a long time, even after all the viruses from the first infection have been destroyed. They stay in the ready-mode to quickly recognize and attack any returning viruses or bacteria.

Quickly making lots of antibodies can stop an infection in its tracks. The first time your body fights a virus, it can take up to 15 days to make enough antibodies to get rid of it. With the help of Memory B-cells, the second time your body sees that virus, it can do the same in thing 5 days. It also makes 100 times more antibodies than it did the first time. The faster your body makes antibodies, the quicker the virus can be destroyed. With the help of Memory B-cells, you might get rid of it before you even feel sick. This is called gaining immunity.

B cell memory: understanding COVID-19 (2021/02/09)

If the amount of Abs [antibodies] in circulation drops, or if the pathogen varies from the initial infection, the shield may not be protective, and a re-run of the response would be required. This response, triggered by re-exposure to the same or a closely related pathogen, uses the memory B and T cells, incorporating the information acquired in the first response by starting with cells that have already been selected as being strongly reactive. This head start makes memory responses faster, larger, and of higher affinity than the initial response, allowing for rapid negation of the pathogen, often before symptoms develop.
...
Within GCs [germinal centers], B cells rapidly proliferate and, remarkably, deliberately mutate the DNA encoding the epitope-binding component of their antigen-binding receptor, potentially changing its affinity. This occurs as repeated cycles of proliferation, mutation, and selective survival of those B cells with improved binding affinity to antigen. This “selection of the fittest” continues for the duration of the response or until antigen receptor binding strength reaches a maximum, meaning that B cell affinity is improving as the response progresses.

Why are T cells called T cells
T cells (thymus cells) and B cells (bone marrow- or bursa-derived cells) are the major cellular components of the adaptive immune response.

I wasn't even familiar with this organ of the human body:
Thymus
The thymus is located in the upper front part of the chest, ... behind the sternum, and in front of the heart. It is made up of two lobes


Update, 2022/05/29:
Here's another article that mentions memory B and T cells benefitting from delaying the booster, if you've recently had a COVID infection:

Is a second COVID-19 booster right for me?

“An infection acts as a kind of ‘immune boost,’” Ferullo explains, “Getting a booster shot too soon thereafter runs the risk of interrupting and restarting an immune-building process that the infection began,” he explains. “The longer those memory B and T cells have to mature, the better equipped they will be to fight a new infection, so it makes sense to delay a booster for a few months after recovery.”

I went to Kroger today, and the self-checkout had an option for no receipt (which I selected). There was no option for an emailed receipt. So after getting home, I logged into my Kroger account (based on the Kroger card) to check, and it has a "My Purchases" page. It lists each time I've shopped there with my card, listing everything purchased, along with the prices and even pictures of the items. Pretty neat. I hadn't noticed that the last time I logged in, when I was checking out the digital coupons which they now advertise sometimes on the shelves.

In 2011, Kroger phased out BPA from their receipts as well as their store-brand cans:
https://www.thekrogerco.com/wp-content/uploads/2017/08/Statement-BPA.pdf

But they switched to BPS in the receipts, which is just as bad:
https://www.ecocenter.org/healthy-stuff/reports/receipt-paper-study-2018

As of 2016, 62% of their store-brand cans still had BPA:
https://saferchemicals.org/retailers/kroger/

How a light touch can spur severe itching: Aging linked to decline in cells that control itch response
The article states: Itching caused by touch becomes more common as we age

That's new to me. Maybe that is why I'm becoming more sensitive to the tags in my clothing.

DNA Double Take - genetic chimerism and mosaicism is much more common that previously thought.

I accidentally bumped my foot against the side of a mirror as I was hurrying to the kitchen, and ended up with a small gash in my toe, and blood dripping all over the kitchen floor. It seemed at first that it wasn't going to stop bleeding, even with me pressing against the cut with paper towels. But after about 20 minutes, it had slowed down enough for me to clean it and put a bandage on.

If such a small cut can bleed that much, I wonder how doctors deal with really big cuts... how they get those to stop bleeding. Just bigger bandages, I guess.

.

I was thinking today about old bodies versus young ones... about an old person's cells versus a young person's cells. How are they different? They must be different, otherwise the old person wouldn't seem aged. No dry wrinkly flabbly skin, no gray hairs... but how are they different? Cells regenerate in old people too, don't they? Do certain cells just stop working, and don't regenerate new working versions anymore, when one gets old?

Some parts of aging might not be the cells, but the other stuff in one's body... accumulated toxins... plaque in the arteries...

And then I was thinking about how a forty-year old man and a forty-year old woman can have a baby, and the baby's body is brand new, not forty years old. Two old bodies producing a new, young body. How is that possible? What is so special about the egg and sperm cells, that they produce a new young body, as opposed to another old body? And if 2 old bodies can produce a new young body like that, why can't they regenerate their own bodies with young cells, to avoid all the unpleasant side-effects of aging?

And then I was thinking about that sheep they had cloned, and wondering how exactly they had done the cloning, because I don't remember the details.

And I was thinking about how women in the future who hadn't found any compatible male partners to have a family with, might decide to have a child-clone of themselves; no-one else's genes involved. Men would have a harder problem doing the same, as they would need to find some female willing to carry the clone-baby to term, and give birth to it, unless they come up with a way of developing babies in the future without the whole pregnancy part.