Metrics across the board have decreased again last week in Easthampton. The rate of decline is much slower, but it has to be once you reach lower numbers. The 7-day average case rate sits at 27.3 new cases per day per 100,000 population. We last saw these numbers last year just a few times – back in April of 2021, after the winter peak, briefly in September of 2021, at the height of the delta variant peak, and in December of 2021, on the way up for the record-breaking omicron variant peak (see additional visual A). All signs continue to point to real declines in viral activity, including measures of virus concentration in sewage* in Massachusetts. We know that cases are underreported because of the results of home testing are not included in case counts. Regardless, the fact that all metrics are following a consistent trend and that the metrics match information from wastewater data indicates that this is a true substantial decline in cases.
*We test sewage? Yep. The quick overview, if you’ve missed this metric thus far, is that a company from Boston called Biobot conducts wastewater epidemiology. Specifically, they monitor the concentration of the SARS-CoV-2 virus in wastewater. This is an example of anonymous passive population-level epidemiology: no one has to “do” anything to be part of the study (which means no one gets missed), there’s absolutely no individual level data collected (and no possibility of ever getting individual level data), and the resulting information is a leading indicator of COVID-19 activity, meaning that the concentration of virus in sewage is usually just ahead of case rates and definitely ahead of any burden on the health care system. It's incredibly useful data and is really reassuring that viral activity is substantially lower now than it was a month ago (see visual B). Biobot conducts wastewater testing throughout the United States and their website provides an overview of virus concentration by area. I’ve included their depiction of virus concentration in Hampshire County.
The CDC released updated guidance on February 25th, 2022 combining case rate and hospitalization data. The goal of the updated guidance is to help communities assess transmission and risk, and determine how to use that information to make decisions about when to lift restrictions and when to put restrictions back in place. The change in metric threshold is a reflection of learning more about the virus and the decoupling of cases and hospitalizations due to vaccine and prior immunity. The CDC table is included (see visual C), and the center of the dashboard is a version of the table I adapted to use more familiar language (the information / metrics are all the same). Essentially, the CDC determines if community transmission and corresponding risk is low, medium, or high depending on local hospitalizations, allowing for more or less tolerance for hospitalizations depending on community case rate. When the case rate is high, we can tolerate less in our hospitals before needing to tighten up restrictions. When the case rate is not high, we can tolerate a bit more in our hospitals before tightening up restrictions.
The CDC recommends universal masking when community transmission is high, that some folks mask when community transmission is medium, and that nearly all restrictions can be lifted when community transmission is low (see visual D). They provide an easy way on their website to check the transmission category of your county. https://www.cdc.gov/coronavirus/2019-ncov/your-health/covid-by-county.html
The overall response to this guidance from epidemiologists has been positive, with a notable caveat: public health is about protecting everyone, including the most vulnerable, and as such, is meant to be population level advice. These guidelines are a huge step forward and really needed, but the associated recommendations for risk mitigation is individual-level advice for "most" people – meaning, those who are generally healthy and who are vaccinated. There’s actually a whole bunch of people this individual-level advice doesn’t apply to, and you’re left to determine a) if you’re one of those people who it doesn’t apply to, and b) what to do about it (meaning, which restrictions to keep in place personally). In general – if you’re at risk because you’re unvaccinated, immunocompromised, or have other chronic conditions on the “high risk” list (or you live with someone who matches those characteristics), you’ll probably want to be more cautious than this guidance suggests, including continuing to mask if you live in a community with medium or high transmission.
Relatedly, two “toolkits” have been released recently about mitigation factors in schools. One is called “Urgency of Normal” and the other is called “Urgency of Equity.” This is a tough subject – both toolkits have experts who have worked together to create the information presented. Here’s what I can tell you – neither is ground-breaking. Essentially, one group urges schools to return to a pre-pandemic normal based on the assumption that COVID-19 is an insignificant threat to children and one group urges not necessarily that all mitigation strategies should be dropped and that we need to make decisions based on data with consideration of protecting all parts of our community, including the vulnerable. I can also tell you how the toolkits are being received in the field – the Urgency of Normal toolkit has been widely criticized by many of the leading epidemiologists in the field.
A major part of this discussion is centered on the severity of COVID-19 for children. It’s still difficult to compare the severity of COVID-19 with the severity of the flu. The flu is a useful disease for comparison because while we experience increases in flu cases, including hospitalizations and deaths, we don’t enforce *many* risk reduction measures to avoid that outcome. Note that we do have an approved flu vaccine for everyone ages 6 months and older. That’s a big difference! It means that each individual has a good degree of control over their risk of a severe flu-related outcome. We’re not there yet with COVID-19 – there is no approved vaccine available for those under 5 years old and we’re probably at least a month away from significant progress in getting a vaccine approved for that age group. That’s an important point - the degree of risk associated with COVID-19 infection is only modifiable for those who are 5 years of age and older.
That was many words still not answering the question. Which is more severe for children, the flu or COVID-19? For both diseases, children who are unvaccinated have higher risk of infection, hospitalization, and death. Here is some data based on today, where those 6 months – 18 years can be vaccinated against the flu, and only those 5-18 years can be vaccinated against COVID-19:
- For the past 20 years, there have been 37-199 confirmed pediatrics flu deaths per year. The CDC acknowledges that this is likely an under-report and the true number of flu fatalities is probably 1-2x the confirmed number.
- There are a total of 970 confirmed pediatric COVID-19 deaths since March 2020. The APA acknowledges that this is likely an under-report but as of yet we do not have an estimate of the true number of COVID-19 fatalities. It’s reasonable to assume that underreporting would be similar between flu and COVID-19, so probably the true number of pediatric deaths in 21 months is 1-2x this number.
The time period is different, which makes comparison difficult. Consider two flu seasons as a comparison - even two of the worst flu seasons would result in about 400 confirmed pediatric deaths. Again, there have been 970 confirmed pediatric COVID-19 deaths in just under 2 years. Regardless of what metric you use (cases, hospitalizations, or deaths), COVID-19 has been more severe than even a bad flu season. We might see that comparison change once the vaccine has been available for all children 6 months – 18 years for a year. We will have to wait and see on that.
What’s the bottom line? Children need to be in school, learning. When it’s safe, they should do so with fewer or no restrictions. But for some time, that might mean continuing various mitigation measures to protect all children, but especially the most vulnerable (remember, individual vs. population level recommendations). The CDC guidelines don’t specifically address schools. It will be left up to school districts to decide. Are risk mitigation measures in schools actually working? Again, this is a hard question to answer, but here’s what I can tell you: data indicates that there have been many communities where schooling has been disrupted during the omicron surge. The New York Times just released information about school disruption in the US during January. About 50% of children in the US missed a week or more of school in January as a result of school closings (see visual E). That has not happened in Easthampton - there are certainly students who were out for isolation, but there were no school or classroom closings. The vaccine uptake in Easthampton and risk mitigation measures in the schools are surely part of why we have had minimal disruptions.
There's a lot changing right now, as we consider how to move forward in the context of likely at least a few months of low COVID-19 activity. Tensions are running high, and I hope above all else, we will remain kind to each other as we navigate this challenging time.
Megan W. Harvey, PhD, MS (she/her)
Follow-up on Denmark after lifting restrictions
Denmark lifted most COVID-19 restrictions as of February 1, 2022, including masking mandates, vaccine requirements, and mandatory isolation for those infected. I thought it might be helpful for us to check in on the situation there, and specifically to think about why the decision was made and if there have been negative consequences as a result. It's not a perfect prediction of what might happen next in the US, but it will certainly provide some insight.
First and foremost, the proportion of the population that’s vaccinated in Denmark and in the US is very different (see visual F). On February 1st, 2022, 81.3% of Denmark was fully vaccinated and 61.4% of Denmark was fully vaccinated with a booster dose. On that same date in the US, 61.9% of the US was fully vaccinated and just 27.1% of the US was fully vaccinated with a booster dose. This difference in risk of infection and serious illness cannot be overstated. The day that Denmark lifted their restrictions, they were at substantially less risk than the US.
Looking at the case rate in Denmark and in the US, we can see that Denmark has been experiencing a greater case rate per million people than in the US – and this is true before and after lifting most COVID-19 restrictions (see visual G). At first glance, perhaps it looks like there was an enormous surge in cases once Denmark lifted restrictions, but actually, that surge was well underway on February 1st. In fact, cases in both Denmark and the US were declining on February 1st. After restrictions were lifted, there was about a two week increase in cases again, but cases have been declining again in Denmark since mid-February. There was no such increase in cases in the US.
Cases are a less important metric in this stage of the pandemic than the rate of severe illness and death. The rate of severe illness in the US, as measured by the number of hospitalized patients per million population, has been steadily decreasing since the peak in mid-January 2022 (see visual H). In comparison, the number of hospitalized patients per million population in Denmark was slowly increasing until about early February, and since then we are seeing a slightly faster increase in hospitalizations. I do want to highlight though, that this trend does not extend to the most severely ill patients who are in intensive care (see visual I). The trend in hospitalizations and patients in intensive care in the US peaked in mid-January and has been declining since then – in other words, the trend in those needing intensive care in the US mirrored the trend in hospitalizations and in cases. In Denmark, however, the case rate increased, the rate of hospitalizations increased, and notably, there is only a very small associated increase in those needing intensive care - in other words, the trend in those who needed intensive care in Denmark did *not* mirror the trend in hospitalizations and in cases. This is very likely explained by the big difference in vaccination and booster rates in the US and in Denmark.
Finally, the difference in the case fatality rate associated with COVID-19 infection is stark between Denmark and the US (see visual J). The case fatality rate provides a standardized measure of how many of the people who are infected end up dying as a result of their infection. The case fatality rate changes over time because it depends on things like if there are treatments available and if hospitals are overwhelmed and not able to provide high-quality care. You can clearly see that the case fatality rate is far higher in the US than in Denmark. In other words – if you are infected with COVID-19 in the US, you are at far higher risk of dying than a person who is infected with COVID-19 in Denmark. There are many reasons that this difference exists, including differences in our healthcare system, access to care, and comorbidities, but the difference in the proportion of the population that is vaccinated is absolutely a major factor in that difference.
So, back to the original question. Denmark decided to lift most COVID-19 restrictions in the midst of a surge, in the context of being a highly vaccinated and boosted population – did that have negative consequences? I suppose it depends on how you measure negative consequences. Since that time, cases rose and remain incredibly high. Hospitalizations have increased a lot, the rate of those in intensive care and the case fatality rate has increased but by a much smaller percentage. There are epidemiologists who are critical of the timing and approach and there are epidemiologists who point to the degree to which the increase in cases and hospitalizations has not translated to an increase in the most severe outcomes and would call the approach a success. We don’t need a definitive answer to that question, we just need information about if what they did would work here. The vaccinated population in the US is nowhere near the vaccinated population in Denmark, and almost all epidemiologists agree that lifting most COVID-19 restrictions in a similar manner in the US would have major impacts on severe disease, death, and the healthcare system. Many segments of the population in Easthampton, however, do resemble Denmark's vaccination rates more closely than average US vaccination rates – notably, vaccinations are low among 5-11 year olds and 20-29 year olds. And of course, the 0-4 year old population does not have access to a vaccine yet.