It has come out that sometime in August of 2019, the SARS-COV-2 virus was leaked out of the lab in Wuhan, China with very likely intent to begin a world-wide economic collapse as an overt act of war committed without official declaration by the Chinese Communist Party. One only has to understand that NORAD at Cheyenne Mountain is still sealed as it has been ever since President Donald J. Trump signed an executive order to do so on March 27th, 2020 to realize that we have been at war and, since lock-down conditions still persist in multiple states in the US and likewise in multiple countries around the world, we are still at war.
Logic then dictates that if world treaties prohibiting the use of biological weapons were violated once in an overt act of war (even if said war was undeclared) without consequence, there is nothing to prevent the offending party from committing additional violations of war treaties in subsequent attacks. SARS-COV-2 has already mutated to the Omicron variant, a significantly weakened virus that spreads rapidly, has symptoms greatly reduced in severity, is easily overcome by an immune system that has not been compromised by experimental mRNA therapy injections and establishes immunity to all other variants, consequently the so-called "pandemic" is over, and will likely officially be over within a few months.
If the original weapon did not cause the intended devastation (and it did cause devastation, but presumably not the amount of death that was expected by the ones responsible for the development of said virus), then it stands to reason a second attempt would be made to further reduce world populations by a significant margin, making it that much easier to conquer them with subsequent attacks. The US has a massive amount of land viable for farming, consequently attacks delivered by nuclear weapons are less likely than attacks of poisonous chemicals that can be more easily dispersed after the attack.
The best way to survive such attacks would be to be prepared for them. Other essentials would be preserved sealed food, and sealed water or water filters to protect them from contaminants.