The Healthy Washington — Roadmap to Recovery plan that will guide reopening of many sectors of the economy is based, in part, on a pattern of reduction in the number of cases of Covid-19 reported to the Washington State Department of Health. Two weeks into the program, none of the regions have met the opening criteria.
The past couple of months have not been encouraging, with Covid cases spiking across the region and state. The downward trend in the summer began to reverse itself as people went back indoors, and health authorities feared the impact of holiday travel and gatherings later in the fall. Figure 1 shows the trends in reported cases in the three county region from early June through early January. Due to the extreme unevenness of daily reporting procedures, the data is presented as a trailing 14-day average.
The fears of holiday gatherings appear to be borne out. Case reporting lags actual infection due to incubation time and testing time, so the spikes a week or two after the major holidays suggests that those holidays did contribute to spreading of infection.
The next assessment date for possible reopening will be Friday, January 22. By that time, the largest reporting day in recent weeks will have fallen out of a 7-day average, and the second largest will have fallen out of the 14-day average. So there may be an actual downward trend in cases. But that is just one of the four criteria, so it is not clear whether indoor dining can resume next week.
The Healthy Washington program is based on multi-county regions of the state, unlike the first reopening plan which was based on counties. The plan uses a Puget Sound region consisting of King, Pierce and Snohomish Counties. So, we might ask if any one of the three counties is dragging the region down. Figure 2 shows Covid-19 case rates for each of the three counties and for the entire region beginning in June.
Pierce County has had slightly above-average case rates during July and in November and December, but has fallen back around the average in January. Otherwise, the three counties are moving in consistent directions (for good and bad). We will see if the odd uptick in Snohomish County in early January holds.
Case rates were already increasing rapidly in the fall, as people moved back indoors and many activities resumed. There were definitely spikes around the holidays, but although suggestive of a holiday effect, it is difficult to isolate the effects of greater travel and holiday gatherings from the general upward trend. And holidays made reporting by health agencies a bit less reliable.
So, projecting forward into the rest of the winter and early spring is a challenge. There will be fewer big holiday gatherings, but just as much general indoor activity. And vaccination programs initially target older residents who are more vulnerable to the impacts of Covid, but less likely to be spreading it around: the superspreaders will remain unvaccinated for a while. As the state rolls out its reopening plan, the Indexer will track case rates to see how the region is trending.