Although we don’t know for sure, the most likely source of the virus responsible for the pandemic is a Chinese wild animal market. And after the virus took off in people, it has spread to people around the world, and to many species of animals. Tigers, mink, dogs, cats, and other animals can get infected, and some of these species may act as a reservoir. Deer across the United States have high levels of infection. So what are the implications?
This virus isn’t going away
Even if people were to become more cautious and somehow bring the virus under control, it would probably come back due to our interaction with animals. Quarantines, lock-downs, physical distancing and other restrictions on human-human interaction make sense in terms of buying time and protecting the most vulnerable, but they are not enough to control the spread of this virus. Human-animal interaction is going to continuously re-introduce the virus back into the human population.
New Viruses and Variants Arise in Other Species
There have been 3 coronaviruses that have crossed from other animals to humans in recent years: MERS, SARS, and SARS2. Around the year 2000, SARS jumped from Civet cats and tanuki (“Japanese raccoon dogs”) to humans, and it spread sporadically for almost 3 years. It had a fatality rate higher than for the Covid-19 from SARS 2.
MERS (the Middle Eastern Respiratory Syndrome) was first seen in Saudi Arabia in 2012, and there were isolated outbreaks in Asia through 2018. This disease-causing coronavirus has reservoirs in bats and camels.
The original ‘vaccine’ was developed using cowpox, a relative of smallpox that circulates in cows. In India long ago, it was customary for wealthy families to send their daughters to live with the milkmaids on a dairy farm - if they got cowpox, that was typically very mild and it provided immunity to smallpox (which could both disfigure and kill). Eventually, the Spanish word for cow (vacca) was rolled into the new word vaccine.
It’s entirely possible that a milder variety of SARS2 develops in animals the way that cowpox did. That would be great. It’s also possible that the virus develops into new varieties in other animals that are more lethal when they cross back to humans… this is not the most common thing to happen, but it does happen, and it can have severe consequences.
More Vaccine Research Needed
Although the vaccines against SARS2/Covid-19 that were developed in 2021 are very effective in reducing severe illness and death, they are a very limited tool. Immunity declines fairly rapidly, and the current shots seem to lose much of their advantage over time. And the SARS2 virus mutates rapidly, and the virus variants that spread fastest are the ones that can evade the protections offered by the vaccine.
The Holy Grail of coronavirus vaccines would protect against all variants of SARS2 - and SARS and MERS. Protection would be long-lasting. It would also protect against the types of coronaviruses that are often responsible for some types of the common cold. It’s not clear that such a vaccine is achievable. The old thinking was that the common cold is so variable and so mild that it isn’t worth the costs of developing a vaccine. But we can do better than what we have; the stakes are high.
I take issue with the reasoning "the virus lives in other animals" therefore "the virus isn't going away". There's a huge list of possible states between the extremes of "let it rip" and "complete elimination".
Many other pathogens aren't completely eliminated, but we suppress and control them so well that they're not really a problem at least in high income societies. Examples are cholera, tuberculosis, malaria. Malaria for example used to be rampant in southern Europe, many ancient Romans got it often.
I'm excited about non-pharmaceutical interventions which don't require individuals to change their behaviour, for example better ventilation, filtration and sterilisation of the air. Similar to how cholera is controlled with clean water, we can suppress covid and other airborne diseases with clean air. And covid can't really mutate away from it like it can with vaccines. I saw this paper about stuff that might help https://www.nature.com/articles/s41598-022-08462-z You have a bunch of UV lamps on ceilings. The wavelength they use doesn't harm skin or eyes it seems. They could be placed in high risk places like schools, nightclubs, public transport etc, and they quickly destroy viruses and bacteria floating in the air. Of course until then even low tech solutions like better ventilation will help. And masks, good ones which fit well, the virus also can't mutate away from those.