7 April 2021 Blog: Towards More Aggressive Reopening in Los Angeles County
In near simultaneous statements, Governor Newsom announced plans for a wide reopening of the state (link: https://abc7news.com/newsom-update-green-tier-california-system-orange-rules/10491250/), while Los Angeles County officials revealed that COVID-19 case declines have ‘stalled’, risking such plans (link: https://patch.com/california/los-angeles/las-coronavirus-case-rate-levels-thwarting-more-reopenings).
Can both be true? In fact, yes. But in what seems to be typical Governor Newsom impulsiveness, he has now done away with the tier system, decided the state will now move as a monolith instead of county-by-county, and has pinned reopening on “adequate vaccine supply” (undefined) and hospitalization rates.
My biggest gripe(s) are his scrapping of the tier system and the use of hospitalization rates – and I’m not thrilled by moving away from county-by-county granularity but I can live with that. The California tier system which I have critiqued for being arbitrary in its choice of numeric cutoffs, does at least attempt to model a well constructed tier system advanced by Harvard’s Global Health Initiative (link: https://globalepidemics.org/wp-content/uploads/2020/06/key_metrics_and_indicators_v4.pdf). Using hospitalization rates to gauge reopening makes little sense as it is a lagging indicator. In other words, it takes time for individuals to become sick enough to require hospitalization so any policy based off of hospitalization rates will necessarily be a delayed reaction.
It is better to use incidence (rate of new cases) and prevalence (rate of active cases) in the population to guide policy. More cases lead to more hospitalizations which lead to more ICU beds being filled and ultimately leading to higher mortality rates. We have heard this tune before.
To this end, I have continued to calculate and track the incidence and prevalence rates of COVID-19 here in Los Angeles. I have truncated the figures to begin the first week of January 2021 rather than spanning the entire pandemic. Figure 1 presents the incidence (i.e. new case) rates which have declined sharply from 143.7 new daily cases per 100,000 population the first week in January to 4 currently – a 97% drop.
Similarly prevalence rates (the number of active infections at a given time) have also decreased since the first week of January (Figure 2) from 24% to 0.1%
Prevalence rate numbers have gotten so low that it is now better to express them in values per 100,000 population. For the week ending January 12th 2021, there were 24,412 active COVID-19 cases per 100,000 population. For the week ending 3/30/2021, there were only 64 active COVID-19 cases per 100,000 population. As an analogy, a completely packed Dodgers Stadium in January would have had 14,647 fans with COVID-19 – but today only 38 fans in the same stadium would have the infection.
Dr. Ferrar is correct to be cautious about the leveling off in case declines but, once again, misses the mark on what needs to be done about it. In fairness, so does California’s Health and Human Services Secretary Dr. Mark Ghaly who states it is a “race to get people vaccinated.” What both should be doing instead is redoubling contact tracing efforts which are abysmal for Los Angeles County (link: http://publichealth.lacounty.gov/media/coronavirus/data/contact-tracing.htm). Cumulatively, the County has only completed tracing for 44.8% of cases and in the last 7 days (despite a massive decrease in case load), have only attained a 51.0% completion rate. For effective contact tracing, the County needs to attain a 95% completion rate.
At the very outset of the pandemic, Trevor Bedford (a computational biologist at the Fred Hutchinson Cancer Center in Seattle) noted that COVID spread is analogous to smoldering fires that can then flare up and spread widely. It is not always clear why some fires stay contained and others spread widely, but each needs to be treated with care. This visualization remains true today. By simply watching case or hospitalization or ICU rates, we are solely reliant on vaccination efforts which have been way too slow already and are leaving swaths of people left behind. But we can do more! Basic test, trace and isolate measures which both the State and County seem to have abandoned in favor of complex scheduling software for vaccine appointments are precisely what can eliminate those smoldering infection pockets.
The question is whether or not our health officials want to commit to such a labor intensive process. Doing so would allow the State and County to be more aggressive about reopening filling restaurants and stadiums to capacity, returning to a sense of normalcy. But that is not the stance that has been taken to date, and I have little optimism that their approach will change. Instead, we are left with a passive, inflexible government – in charge of vaccine distribution and unwilling to douse the few (but dangerous) remaining flames of infection.
𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿