As we suddenly unmask to celebrate the seeming end of the pandemic, we need to recognize the consequences of premature celebration. I certainly understand the desire to be done with all of this, but SARS-COV-2 doesn’t care what we want. Those insisting that we move forward point to falling incidence and death rates as evidence that it is time to move on, but the curves are deceptive. A closer look reveals a hidden 4th wave and should warn us to be cautious.

Consider the following exchange that I recently came across the following exchange on Twitter.

COVID-19 incidence leveled out and even rose despite rising vaccination rates.

On the surface, @BleatrKropotkin’s version of events seems compelling. If we look at the COVID-19 incidence over the course of 2021, the data are encouraging. Cases started to decline during the second week of January and appear to have been flat or declining ever since. Look more closely. In mid-February, there was a dramatic change in the rate of decline. Late in March, cases actually began to rise. Epidemiologically, there is only one explanation for this. The reproduction number is rising. That means that each case is finding more opportunities to cause new cases. For that to happen, something must have changed in the behavior of the population over the course of February to cause an increase in risk. That change persisted and got worse over the course of the next month. Even when cases did decline, they did not decline as rapidly as the had in late January.

The story of this past winter is familiar to us all. Cases began to rise but, not fully grasping the implications of exponential growth, we responded slowly, waiting until the fire was raging out of control before sounding the alarm. Then, before the fire was fully out, we called it quits. But there was still enough fire and fuel around to do more damage. We had an opportunity to put the fire out. When it blazed again in a 4th wave, the only thing that saved us was the vaccines.

The 4th Wave

During two month window from February 19 and April 19, US vaccination rates rose from 12% to 40%. That should have made it easier to control the pandemic. Despite this advantage, with vaccination rates soaring, incidence was flat or rising. In other words, we blew it. The hidden 4th wave doesn’t look so bad compared to what we’ve been through, but that’s the wrong comparison. Circumstances hid the 4th wave, but it never should have happened at all.

To see the hidden 4th wave, imagine what could have been. What if we had been able to extend the reduction in transmission that began in mid-January? Let’s graph this out. If we extend that decline past mid-February, we might have been near zero cases by mid- April. If we had, many, if not most of the 5 million cases that occurred after that point would have been avoided. By the same argument, we might have avoided as many as 50,000 deaths.

And this simmering 4th wave isn’t over. Ending the mask mandates with less than 50% of the population vaccinated once again misses an opportunity. It will almost certainly result in cases and deaths that might have been avoided. The fourth wave might not have been as dramatic as the second or the third or as startling as the first but, tragically, it might have been the most avoidable. With vaccination rates rising, control should have been easier than ever. How did this happen? Perhaps we have simply become inured to the disease. Perhaps we had just become tired of dealing with it. But the pandemic, however, does not end when we decide we are done with the virus. It ends when the virus is done with us.