 For more videos on people's struggles, please subscribe to our YouTube channel. The ups and downs in the Omicron wave continue across the world. While the global picture provides for some signs of hope, the situation varies from country to country and even between regions. Understanding the pandemic calls for the right nuanced analysis of local factors and dynamics in its spread. There have also been new studies which theorize the emergence of variants and the factors involved. These studies have interesting implications for public health policy in the time of the pandemic. Immunologist Dr. Satjit Rat talks about some of these issues. What we've been seeing over this past week in the COVID-19 pandemic is what appears to be a steady retreat of the Omicron wave as it were. On the one hand, this is certainly true globally. Global case numbers are dropping in many countries. Case numbers have been dropping for weeks now and hospitalization numbers are reducing. So in a variety of ways, the public health significance of the COVID-19 wave in Omicron times seems to be less and less crisis more. There are a couple of points that I think all of us should take note of. In the first place, when we look at added numbers, totaled numbers across political geographies, those can hide underlying differences that carry public health significance and meaning. So to give a couple of examples, across the European Union, case numbers are dropping if you just count European case numbers. But that's not true for Germany. German case numbers are rising. Test positivity rates in places like Germany and France and Austria are still rising. So within a total population of the European Union, if you look at it as a single entity, the wave seems to be on the way. But within it, there are many divergences with very different lived local realities that still need local substantial public health responses. A public health response cannot be simply determined for a large total. Exactly similarly in the global south, in South America, there is an example that stares us in the face with very different trajectories at the moment between Argentina and Chile. Again, one shows a Omicron COVID-19 trajectory of recent days that's quite different from the other. And in all of this, the underlying idea that is absolutely essential, especially from a public health activism point of view, is that local evidence, local numbers, numbers of tests done, whether those tests are being done consistently as a matter of statistical sampling from communities or not, what the test positivity rates are, what the hospitalization rates are, these are local pieces of evidence that are absolutely essential to mount an appropriate, inclusive, effective public health response to the local realities of the COVID-19 pandemic. This is a crucial point to keep in mind, particularly because as national or regional numbers begin to go down, a sense of triumphalism, particularly from governments, is unsurprising and to be expected and can lead to major gaps and lacuna in local public health responses. And as the Omicron wave receives, Omicron lineages are not one virus strain, they are a whole group of related virus strains. It's interesting to think about as we move forward what this analysis of Omicron lineages tells us about policies going forward. So there is in this context, it's of interest to note that there's a relatively recent analysis published in the Journal of Genetics and Genomics from the Chinese Academy of Sciences in Beijing, where scientists have analyzed Omicron lineages, the genetic sequences of a very large number of Omicron isolates, as well as non-Omicron sub-scope to isolates, and have made two or three points of interest. One point of interest is that there seems to be some selection pressure involved in the emergence of the Omicron strain based on vaccine evasion. And this seems to be the first time in a year and a half of almost a year and a half of vaccination, a year and two months of vaccination, that widespread vaccination has exerted evolutionary selection pressure on the virus so that the virus has undergone selection for being able to grow in vaccinated people. That's a lesson for the future because if we allow uneven vaccination in vaccine inequity to persist, then we are allowing large amounts of the virus to grow and to be tested in evolutionary selection for vaccine resistance strains to emerge. This is one lesson from that analysis. The second lesson is equally interesting and that lesson is that it's at least plausible that the Omicron lineage may have resulted from rodents, rodent species, particularly mice, having gotten infected by variants from humans, having the virus having grown and undergone changes in rodents, in mice, and then some of those variants from mouse virus populations may have come back as the Omicron lineage. Regardless of whether that analysis is robust, well supported, and correct or not, what it provides is a timely reminder of a basic fact with SARS-CoV-2 and with coronavirus in general. They are zoonosis. They have non-human species that can function as hosts. In addition to bats and humans, we've known that minks, which are members of the weasel family, cats and tigers and lions and leopards, members of the cat family, hamsters and now mice as members of the rodent family, all of these various mammalian species can serve as hosts for reservoirs of SARS-CoV-2. And under these circumstances, exactly like the influenza virus family, non-human host reservoirs mean that it's going to be impossible to eradicate the virus. We need a global public health-oriented monitoring system that carefully, in space and time, identifies sequences, considers them their biological characteristics and designs vaccines from a public health point of view as and when necessary. An ongoing globally integrated public health response is likely to be needed. This recent paper and its analysis are reminders for us of that continuing need that the pandemic has taught us about this much for this week.