Data reveal deadliness of COVID-19, even in young adults

COVID-19 death memorial flags
COVID-19 death memorial flags

Victoria Pickering / Flickr cc

Even though all-cause mortality due to COVID-19 may not be known for a while, two new studies highlight that 173,300 (79.5%) of excess deaths from March through August were COVID related, with 4,535 deaths occurring from March through July in younger adults ages 25 to 44, or 38% of all excess deaths in that group.

Data from the latter study helped inspire a New York Times editorial yesterday by the likely next director of the US Centers for Disease Control and Prevention (CDC) and her colleagues, who tried to dispel the myth that the disease is not deadly in younger adults.

The first study, published in the Annals of Internal Medicine, found that almost 220,000 excess deaths occurred between March and August, even after adjusting for a growing and aging US population. The second study, a JAMA research letter, reported that COVID-related deaths in young adults exceeded opioid overdoses, a leading cause of death in this age-group, in 20% of US Department of Health and Human Services (HHS) regions during the first half of the pandemic.

As the Annals researchers write, though, "Estimating the true burden of COVID-19 will require continued monitoring of excess deaths by cause. Additional non–COVID-19 deaths due to the pandemic will probably occur for many years because of delays in cancer screening, surgery, and other essential health care."

Excess deaths are the number of deaths above the expected number of deaths, often predicted by past years' mortality.

Adjusting overall excess deaths in elderly downward

After adjusting mortality data to reflect an aging US demographic, 173,300 (79.5%) of the 218,000 excess deaths from March through August were related to COVID, according to the Annals study. Without this adjustment, 57.5% of 301,400 excess deaths were COVID related, but the absolute number of COVID-attributable deaths stayed the same.

The researchers pulled mortality data for Mar 1 to Aug 31 from the Centers for Disease Control and Prevention (CDC) and the US Census Bureau, using provisional data as needed, and compared them to a predicted mortality rate calculated by looking at population data from 2015 through 2019. To increase accuracy, the researchers also factored in 2020's 10% increase of residents 65 or older, an additional 5.04 million persons.

During each pandemic month in 2020, death rates were higher across all age-groups 15 years old and above, with the largest absolute increases in the oldest populations. For those between 75 and 84 years old, there were 44.3 more deaths per 100,000 person-months, which is the total number of deaths during the month divided by the estimated population of that group, multiplied by 100,000. Those 85 and older saw an increase of 138.7 deaths per 100,000 person-months.

Deaths not due to COVID had surges in April and July, with a lull in May and June. The most common causes for people 25 to 64 were heart disease (16.0%) and diabetes (8.6%), and among people 65 and older, the leading causes were Alzheimer disease (67.4%) and diabetes (48.3%). (More than one cause can be listed on the death certificate.)

However, the pandemic may have affected these deaths as well because of healthcare disruptions and patient reluctance to seek services.

Surprisingly, 20,500 fewer deaths due to cancer occurred during the study period. The researchers speculate that COVID may have superseded cancer's adverse outcomes. For instance, on Nov 14, 11,000 COVID deaths in the United States were in patients who had cancer.

Thousands of COVID deaths in young adults

During the first 5 months of the pandemic, 76,088 all-cause deaths occurred among young adults, with each month showing excess, according to the JAMA research letter. The researchers found 11,899 more Americans ages 25 through 44 have died than expected (18%), with 4,535 (38%) of the deaths caused by COVID-19.

The remaining deaths, the researchers believe, indicate an insufficient amount of COVID-19 detection and reporting in this age group.

A New York Times opinion article written by three US experts notes that, over the past 20 years, 11,000 young adults have died in July. This year, more than 16,000 did.

Among the authors is Rochelle P. Walensky, MD, MPH, nominated by President-elect Joe Biden to be the next CDC director. Although they write that less than 3% of US COVID-19 deaths occur in adults 25 to 44 years old, "what we believed before about the relative harmlessness of Covid-19 among younger adults has simply not been borne out by emerging data."

From March through July this year, according to the JAMA study, young adult mortality increased in each of the 10 HHS regions, and separate surge periods in three regions—in the South, Southwest, and New York and New Jersey—increased the likelihood of mortality by 46%, 47%, and 130%, respectively. In three HHS regions, COVID-related deaths equaled or exceeded the number of opioid overdoses for its comparative month(s) in 2018.

There is no denying the toll that COVID-19 has had on the United States. A JAMA commentary today states that the daily US COVID deaths are equivalent to 15 Airbus 320 jetliners crashing every day. COVID-19 has become the third-leading cause of death in people 45 through 84 years old and the leading cause in those 85 and older. In adults younger than 45, drug overdoses, suicide, transport accidents, cancer, homicide, and other causes of death are still more prevalent.

Still, both the research letter and the New York Times editorial urge people to take notice of the risks young adults have.

Walensky and her colleagues in the Times op-ed write that the country already hit its expected death total for this population (154,000) in mid-November—before the expected holiday surges. "[Following COVID mitigation tactics] is even more important now that safe and effective vaccines are a reality," they write.

"Young, healthy people are low on the priority list for the vaccine rollout. That means that modifying behavior now can save thousands of young lives next year."

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