Prior immunity allegedly didn't exist with COVID-19. How do you explain that?

"Allegedly" is the key word here.

• Natural variation in both immunity and exposure.
• The role of Vitamin D deficiency in immunity to Covid, suspected right from the beginning, has now been confirmed.
• Prior exposure to other coronaviruses can give some limited protection against Covid.
• Exposure to SARS-2 prior to the official start of the pandemic.

We know that some mystery respiratory disease with symptoms exactly the same as Covid was running rampant all over the world, months before the official start of the pandemic in December 2019. That was probably Covid. So what we're counting as "the first wave" was probably the second wave, and there were already many people who had prior exposure.

When a final accounting of the pandemic happens, we will have to admit that while the early strains of Covid were dangerous, the real harm was done by the medical treatment we gave patients: putting them on respirators, refusal to give antibiotics when they came down with secondary infections, refusal to start early treatment, double standards in EULA, and the deliberate involuntary euthanasia of the elderly.

We started with a virus that, with proper care, might have been twice as dangerous as the flu, boosted it to ten times as dangerous by poor medical decisions, then told everyone it was a hundred times as dangerous using misuse of statistics and overcounting of Covid deaths.