@davej Science and medicine are always evolving. So is the Covid virus with many variants that happen because of errors in copying when it is duplicating itself. Some of the variants became so much more infectious because they make much larger quantities of virus. It is in the Coronavirus family which includes the virus that causes the common cold, and even though people get a cold, they don't develop immunity to catching it, so it can happen repeatedly. People have caught Covid multiple times too. I suspect that was one of the challenges in creating a vaccine for Covid. From the beginning when the vaccines were first available, they didn't promise it would entirely prevent Covid; they said it would lessen the chance of severe disease that requires hospitalization and lessen the death rate. That proved to be true after the public started getting vaccinated. They also didn't know how long immunity from a vaccine would last because this vaccine was new so there was no data available, but they have found that booster shots are needed now because the strength of immunity drops off after a period of time. They can measure the antibody levels in a patient's blood. This is just how it is. Perhaps in the future, the vaccines will be better. People spread this virus before they know they are sick.

I have a pre-existing condition, allergic asthma, and I know how exhausted I am if I cannot get enough oxygen because my airway is compromised which makes my heart rate increase and work a lot harder. I am at a higher risk with Covid because of this, and lung damage and scar tissue from Covid would make my disability so much worse. Some patients required lung transplants after Covid. If there is a preexisting heart condition, Covid can make that worse too. You can survive Covid, but may be left with a long term disability and require oxygen or a wheelchair to manage. Covid also causes blood clots and micro blood clots clogging the circulatory system and stressing the heart. Then there is the financial risk and cost of a long hospitalization and insurance may not cover all of it.

To me the risk of not getting an available vaccine to prevent Covid is a much higher risk than receiving a vaccine. Talk to your doctor about your risks. My doctor told me the risks are less (and they are all very low risks) with the J & J. That vaccine is built similar to the way they make a flu vaccine from a killed virus. That is different from the M- RNA vaccines which use a sequence of messenger RNA for the spike protein to train the immune system. My issue with the Pfizer vaccine was because it contained PEG (polyethylene glycol) which apparently I am allergic to. I didn't have a severe reaction. I just got a slight pain in my tongue, a queasy headache and a pain on the jaw/neck junction on the side that got the injection within 45 minutes of the shot. It was all brought under control easily with steroids and antihistamines. Even with that, It was still worth doing. I had to wait a long time before I could find the J & J because they would not give me a 2nd dose of Pfizer. The advice my doctor gave to me to prevent a reaction was to take an antihistamine like Benadryl and 3000 mg of vitamin C ahead of time. I did that when I got the J & J and my symptoms after were a headache and being tired for 2 days, and a sore arm for a week. Then suddenly it all got better and the symptoms disappeared in a few minutes.

It was all worth it, and I will get a J & J booster when I can. Trust your doctor's advice. They are informed about the state of vaccines and what your personal risks may be. There are risks all the time with health and disease. This is one choice you can make to greatly reduce your risk of serious disease and take control of your health.