The vaccine appears to be working similarly to AZT, when it was first administered in the mid 1980s: it worked for months and then...it didn't, for many gay men. Besides which, it was known to have poisonous qualities. There wasn't any other choice at the time.
The comparison doesn't really work between AZT and the COVID-19 vaccine. With AZT (and DDI, DDC, et al) and HIV, because these drugs didn't work on all cycles of HIV replication, the virus was able to adapt and develop resistance to the drugs (if the patient didn't develop lethal complications from the drug itself).
It wasn't until combo-therapy came out- which hit HIV in multiple phases in it's infection-replication cycle- that the virus wasn't able to adapt quickly enough to replicate itself into mutation to become resistant to the meds. That's the key here-
for a virus to develop resistant to either immune responses or to medications, it has to find susceptible hosts to replicate to create the mutation.
What is happening with SARS-CoV-2 isn't connected to the vaccine. The virus is evolving in the way respiratory viruses often evolve- to become less lethal and more contagious. The problem is not the vaccine- it's that the virus is adapting faster than humans. If humans quickly changed their behaviors- physically distancing, masking and getting vaccinated, then the virus wouldn't be given human hosts to mutate. Because we have people who refuse to adapt- by refusing vaccination, by refusing to not gather in crowds and by refusing to wear masks- the virus is being given millions of people in which to continue mutating and becoming more infectious.
Where the HIV and SARS-CoV-2 comparison does work is the human behavior. You probably also remember that we had people who refused to reduce their number of sexual partners, who refused to stop having anal sex without using condoms and who refused to take treatments. We also had a group of HIV-deniers and conspiracy theories who insisted that herpes virus was responsible or alleged that AIDS was actually the government killing off gay people. And now during the COVID-19 pandemic, we have people who were and are continuing to show up at religious events and political rallies without masks, just like during the HIV epidemic, when we had "bug chasers" doing everything they could to put themselves (and all of their future contacts) at risk.
Many people thought they would just get the vaccines, check it off their "to-do" list and that was that. I was not as convinced of that, because the effectiveness of the vaccine could be different for people, depending on their physical well-being at the time. I asked - in a thread - if people were getting an antibody test to see what how effective the vaccine was in their body.
As I recall, everyone said nope, not going to be be bothered doing that. So, now, many people have no idea how effective the vaccine was for them personally - and neither do their doctors. That might have been valuable data in assessing why there are breakthrough cases. Now we're hearing it is likely we will need booster shots.
We need to change the way we view the SARS-CoV-2 vaccines. We're used to vaccines for measles, smallpox and polio that confer lifetime immunity.
We need to think about SARS-CoV-2 vaccines in the way we view influenza or pertussis vaccines- as primarily being a mechanism to keep people from being hospitalized or from dying.
We knew from the early studies that more than one shot was needed to get antibody levels very high. We were so desperate to get everyone's antibody levels up that we were forced to give two vaccines within 1 month. If we had more time to do studies and we weren't dealing with such a contagious virus, we could have given the 2nd dose later- maybe within 3-6 months, so that we would have a more sustained high level of antibodies.
The studies for the clinical trial patients showed us that antibody levels in some patients began to fall around the 6-8 month timeframe, even though they did have good memory cell responses. What this meant is that these patients would get infected and would have mild cold-like symptoms but, once the memory cells kicked in, they would recover quickly when they started cranking out antibodies again.
What I suspect we will find in some of the people who are getting "breakthrough" cases is that they had a low antibody response to their first 2 doses, so they were already starting with lower levels when their antibody levels began to drop off. This made them more vulnerable to symptomatic infection.
But here's what is important: we are getting consistent reports that patients in the hospitals are >90% unvaccinated. That means that the vaccinated people- even if they are getting COVID-19- are getting good enough immune response that they aren't getting pneumonia, they aren't getting sick enough to get admitted to hospitals and they aren't dying.
Let's hope that we also find that those vaccinated patients also don't develop long-haul COVID-19.