Data collected by Britain’s Scientific Advisory Group for Emergencies, Japanese researchers, and the US Department of Agriculture paint a picture of a growing challenge.
This week has been a time of reckoning for major scientific communities and unfortunately a time of heightened denial for many of our leaders. A July 30, 2021 report from the United Kingdom’s Scientific Advisory Group for Emergencies (SAGE) has postulated the probable future direction of the COVID-19 pandemic. In this report, 4 possible scenarios are discussed.
Scenario 1 is that the virus can become more virulent. This can happen by either a combination of point mutations or by the recombination of variants (essentially two variants combining into one). We need to remember that SARS-CoV, the virus which caused the 2003 epidemic, has a case fatality rate of approximately 10% and also uses the ACE2 receptor in cellular entry. MERS-CoV another related coronavirus, has a higher fatality rate, but uses a different receptor. Thus, it is possible for SARS-CoV-2, the pathogen that causes COVID-19, to undergo extensive mutations to become more virulent and still maintain infectivity.
Scenario 2 is that a variant can evade the vaccines. There are 3 proposed mechanisms, all of which can occur.
The first, and, according to the report, “almost certain” one is a variant which avoids the vaccine by a gradual accumulation of point mutations or antigenic drift. Unfortunately, we have a few worrisome variants which could have possibly already accomplished this. Our current Delta variant has almost escaped the efficacy of vaccines, but the lambda variant may be even more problematic. Kei Sato, PhD, from the University of Tokyo and 1 of the 2 lead authors of a study by investigators at the University of Tokyo study, said that, “Lambda can be a potential threat to the human society.”
As stated by Kimura I, et al., “A recent paper also suggested that the vaccines have effectively prevented COVID-19 in Chile (Jara et al., 2021). Nevertheless, a big COVID-19 surge has occurred in Chile in Spring 2021 (WHO, 2021b), suggesting that the Lambda variant is proficient in escaping from the antiviral immunity elicited by vaccination.”
The second mechanism, which may be already starting to occur, is for the virus to infect and spread in another animal species (“a reverse zoonotic event into an animal reservoir”–SAGE). The virus then evolves separately, only to jump back to mankind as an entirely new entity. A report from the United States Department of Agriculture has found that 40% of 385 samples taken from of white tail deer in the states of Michigan, Pennsylvania, Illinois and New York were positive for SARS-CoV-2.
The authors concluded that their research shows deer can become infected by SARS-CoV-2, spread it to other deer, and “exhibit sustained viral shedding.” Even more concerning is that white tail deer “can be abundant near urban centers.” This is very problematic; control may involve special handling and precautions when around deer, or even possible culling.
The third mechanism is recombination of 2 viruses causing rapid and extensive changes. This is 1 of the reasons we need to decrease viral spread, making it unlikely that an individual would be infected with 2 different variants at the same time. With MERS-CoV and SARS-CoV serving as examples, SARS-CoV-2 has a lot of room for significant changes to avoid immunity and still maintain infectivity.
The third scenario is the emergence of drug-resistant variants which can evade antiviral medications. This is likely to happen and has already happened with monoclonal antibodies. However, with so few effective medications, this scenario was felt to have a medium impact on the pandemic.
The fourth scenario, the one I like the most, is that SARS-CoV-2 mutates to a less virulent form, giving natural immunity to the more virulent variants and causes serious disease to disappear. Some feel this may have occurred with the 1918 Spanish Flu. For this to happen the less virulent variant would have to be more transmissible, but this is a rather high hurdle to clear with the highly infectious Delta Variant. Essentially, it would become like the common cold. Unfortunately, SAGE has concluded that this is “unlikely in the short term” but a “realistic possibility in the long term.”
Taken together, the report from SAGE, the viruses’ establishment of an animal host and the news regarding the lambda variant is an extremely deadly mix. We need to come together as a society so we can slow down the spread of this virus so viral recombination will not occur, and genetic drift slows. In addition, we need to formulate strategies to prevent the spread from animal hosts to mankind. Above all, we need to learn how to live with this virus so our pharmaceutical giants can develop and manufacture vaccines faster than the virus can mutate.