Respiratory Disease Update

April 15, 2021

| COVID-19|Flu|RSV
Respiratory Disease Update

COVID continues to decrease in most of the World

While we have said in the past that the COVID-19 Pandemic has turned the corner and even that it is no longer the major social and economic driver for the world, major governments, and the World Health Organization are saying that too. Most importantly, with few exceptions, including small increases in central Europe, new COVID cases are decreasing around the world, and now, based on both government data and indirect indicators of social disruption, this includes China. A major fear over the last month has been that cases, hospitalizations, and deaths will increase due to the massive travel associated with Lunar New Year. This holiday ended last weekend and there has not been any significant increase noted. Increased travel will continue for this business week, so it’s really at the end of next week when we can make the best assessment of impact, but definitely, “so far so good.”. The World Health Organization on Monday made their most positive comment to date, saying that while they cannot yet terminate the global pandemic health emergency, the WHO believes the world has reached a turning point that will allow termination of the pandemic emergency in the coming months. They emphasized the importance of vigilance and continued application of mitigation tools and vaccinations, but clearly expressed optimism that we are moving to a new and much more positive phase.

Currently circulating variants continue to be demonstrably less virulent. For most people, a COVID infection is more like a cold than a dangerous respiratory infection. In the US, which has the most consistent large dataset, 70% of all hospitalizations are in people over 65. And while more difficult to pin down exactly, it appears that over 90% of hospitalizations and deaths are in people with significant risk factors including age, obesity, and major chronic diseases. While a new virulent variant is always possible, historical and theoretical epidemiology tells us that the typical course of viral development is, in fact, to become more infectious but less virulent.

In the United States, as of last week, about 70% of counties in the country have moved to the CDC “low community impact” designation, especially in the western US, but even in the more densely populated east coast area. Major metropolitan areas of the east, including New York City, remain at “moderate impact,” but in most of these areas, the parameters are moving the right direction with the expectation most will move to low-impact areas shortly. Europe is seeing similar patterns with the exception of rising rates in Germany and Austria. Rates are also still high in East Asia, but generally improving with the exception of Taiwan which is seeing a Lunar New Year-associated spike.

Of important note, the feared and initially apparent global Flu and Respiratory Syncytial Virus (RSV) outbreaks have faded and are now lower than typical for this time of year. There is still time for additional peaks and a second influenza peak in early spring is not too uncommon, but at present, there is no indication of case growth. Of note, the flu vaccination rate for this year is at a typical level compared to past seasons at just over 45% of the population in the US.

Future course

Barring the relatively less likely emergence of a new more virulent variant, COVID is becoming a routine circulating disease akin to influenza, with periodic outbreaks due to new variants (as we periodically see with flu), but trending towards impact more like the other four commonly circulating coronaviruses. Additionally, the research and development community did not stop their work with the development of the current vaccines and therapies. The mRNA vaccine technology is now relatively proven and provides flexibility for rapid fielding of slight modifications in case of a highly virulent variant and new anti-viral therapies are in or entering final phases of study in order to ensure there are options if a variant develops resistance to Paxlovid or Remdesivir or for people who have contraindications to the use of those medications. Finally, the “layered defense” mitigation approaches are now well-known and effective.

A major outstanding question is about the future of vaccines. Evidence increasingly shows that for people at routine risk (basically, healthy people below age 65-70), the decrease in risk attributable to boosters is very minimal when the risk from the disease itself is minimal to this population. Currently, most authorities anticipate continued benefits from boosters for at-risk populations, but not the general public. The big question will be whether boosters are recommended in the fall, but we will likely not have an answer for that until mid-summer.  Another major vaccine-related finding recently is that the bivalent boosters had little, if any, benefit over the original vaccine formulation. The response was not any worse, but it was just no better. This calls into question the advisability of “chasing” variants with new vaccines. A characteristic of the human immune system is that it tends to mount the greatest response to the first variant it sees and even when there are new variants, the response is still mainly geared toward the original one. This will have great implications as decisions are made for future vaccine recommendations and will likely mean that only at-risk people will need periodic vaccination.                

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