This question came up when they first started mandating the vaccines saying they had no idea how long the natural immunity of those who recover from Covid19 would last. That was true but they also had no idea how long the immunity from the vaccine would last. But still it was a valid question, so I looked at the Worldometer data and was surprised to learn that two of the countries that had the lowest impact from the pandemic which originated out of China were Taiwan and Vietnam. These are two countries that I would have expected to be hit first. I lived in Taiwan for years and there are many, many people who fly back and forth to China for business reasons. However, these two countries were hit hard by SARS over ten years prior to this. Since Covid19 is very similar to SARS I have hypothesized that the immunity that people who recovered from SARS had is reducing the impact from Covid19 over ten years later. That tells me that natural immunity is durable and effective.
This is actually a very powerful point that condemns the vaccine. We know that this kind of virus mutates at such an incredible rate there is no point in making a vaccine. This is why there is no vaccine for the common cold. Creating a vaccine for Covid19 never had any chance of conferring herd immunity even though that was given as a selling point. I feel quite certain that the real experts knew this but at the same time they might have still thought the vaccine would be helpful, I am not attacking their motive just yet. The problem with vaccinating everyone is that you create an environment that favors the strains that bypass any immunity from the vaccine. This may not have been obvious to "all" the experts, but again, I am certain that the real, real experts knew this would be the case. Perhaps if you could vaccinate 7 billion people in one weekend the vaccine would be beneficial, but barring that scenario, which is patently absurd, the only motivation for pushing this vaccine is that you would make money and in a few months be able to sell another and another. By comparison natural immunity is not to simply one portion of the virus so it is "more durable". It is much harder for a mutation to bypass that immunity.