Everyone at every age has waning antibody levels after ANY vaccine or infection. Our body does not maintain antibody levels forever after vaccines or infections. It is just not how our immune system works. Memory cells are created by B lymphocytes to create new antibodies quickly if/when the threat is seen again. Low antibody levels is not a flaw, it is a feature. They should not be present when there is no threat. It is a bad metric to judge if a vaccine's protection is waning. We need to look at the immune system's response when a new infection occurs. I get that immune systems (and their responses) weaken with age. I think a lot more research needs to be done to determine who actually needs boosters and at what intervals as maintaining high antibody levels is stupid and unrealistic. That should only be a priority to high risk categories, not everyone. Though I'm sure the pharmaceutical companies would love for their vaccines to be mandated for the rest of human civilization and I'm sure politicians would love to get kickbacks from them for making that a reality.
Pat, I would strongly advise to get either the Pfizer/BioNtech or Moderna vaccine as a booster on top of a previous double Sinovac, even if you need to postpone getting it or travel to another town to get it. The protection Sinovac offers is already substantially lower than others, and even China itself is considering other brands for booster shots. I myself will refuse any booster shot from a brand I don't particularly like. I only went for the double Sinovac initially because at the time it seemed quite unlikely that a better vaccine would come available in the Philippines any time soon. That argument no longer holds water.
It's fine. I you're older, get it earlier than six months. My wife managed to get Moderna through people. I never would pass up Sinovac, but that's me.
probably a dumb and perhaps selfish question but is there any where here I could pay for a Pfizer booster?
They had Pfizer in Valencia today as well. Just received my second dose of Astra. Today was not nearly as organized as when I got the first shot (probably because Pfizer was available). Went in at 8:30 and no numbers available, wrote my name down and finished up at 7pm.
I would agree IF they had any actual long-term evidence of the efficacy of different booster shots for all the variables I wrote about here in another posting - until I see the evidence, in a few years time, and after they can unravel the variables, then I have to be true to myself and remain a cynic (or perhaps 'sceptic' is more appropriate as I seek facts).
Antibodies are rather important though! See how well humans were doing against this virus (and other microbial pathogens) until they were helped to produce antibodies. All the other passive methods of immunity against such pathogens (a few examples: the skin and mucous membrane barriers; chemicals in tears, mucus and saliva; different types of white blood cells such as phagocytes; natural production of interferon) clearly failed to stop an epidemic becoming a pandemic within a very short period of time. If antibody levels decline too far then this virus is going to take off again (as it is still doing in many parts of the world) and all the problems of overloaded hospitals will be back. The only reason that many diseases have been put under control in the developed world is because antibodies induced naturally or artificially have been long-lasting and that seems not to be the case for this virus which shows many quite evasive and nasty aspects to its behaviour.
Dr. Estación yesterday allowed that many are requesting booster shots. However, the national IATF does not yet allow it, so that even she (even ako) cannot get it. As I understand from the news, even when allowed, questions remain: only six months after the last (or second) shot?, and hetero veruse homo?, the same or different brand of vaccine. The doctor as usual bemoaned the fact that people are not complying with the protocols. She said something about the borders, but I did not catch it. The pandemic has eased a bit in this province (currently the worse in Central Visayas), and the Level 4 status may be adjusted downward after November 15.