Roundup: New Data on Omicron vs. Delta; Risk Factors Linked to Long COVID; and Booster Effectiveness Reaffirmed

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January 28, 2022

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CDC New Data: Omicron Causing Less Severity of Illness, Compared to Other Variants

Severe illness among patients hospitalized with COVID-19 during the current Omicron-dominant surge  — including ICU admission, ventilator use and death — was less common, compared to time periods of the Delta variant or the first winter surge of the pandemic, according to new data published by the U.S. Centers for Disease Control and Prevention (CDC).

Despite illnesses caused by Omicron being less severe than previous variants, the variant’s high degree of transmissibility has strained many U.S. healthcare systems from the sheer volume of cases, the CDC added.

“Despite Omicron seeing the highest reported numbers of COVID-19 cases and hospitalizations during the pandemic, disease severity indicators, including length of stay, ICU admission, and death, were lower than during previous pandemic peaks,” the CDC concluded.

Omicron was first confirmed in the United States on Dec 1, 2021, and as of Jan 15, 2022, represented more than 99 percent of all sequenced viruses in the U.S.

In the study the CDC compared that six-week Omicron time period with cases and outcomes from two other time-frames: Dec.1, 2020 through Feb. 28, 2021 (the first winter surge of the original strain of COVID); and July 15, 2021 to Oct. 31, 2021, when Delta was the most dominant variant.

“The highest daily 7-day moving average to date of cases (798,976 daily cases during January 9–15, 2022), emergency department (ED) visits (48,238), and admissions (21,586) were reported during the Omicron period, however, the highest daily 7-day moving average of deaths (1,854) was lower than during previous periods,” the study’s authors wrote.

Severity of disease seems lower during the Omicron period because of several factors — wider vaccination coverage in the population, including boosters; immunity acquired from previous infections; and the lower virulence (ability of the strain to cause damage to cells) of the Omicron variant.

Researchers Identify Four Possible Risk Factors for ‘Long COVID’

Researchers who followed more than 200 patients for two to three months after their COVID-19 diagnoses — and had their blood analyzed — indicate that they have found possible biological factors that might help predict if a person will develop “long COVID” — or lingering symptoms that persist long after initial recovery.

The study, published by the journal Cell, and led by researchers at Seattle’s Institute for Systems Biology, found four long-COVID risk factors that could be identified early in a person’s COVID infection.

One of the four factors identified by researchers is the presence of COVID-19 RNA in the blood, which is an indicator of viral load. Another is the presence of certain autoantibodies, or antibodies that mistakenly attack tissues in the body. They are commonly found in auto-immune diseases like lupus and rheumatoid arthritis.

The third factor cited is the reactivation of Epstein-Barr virus, a virus that infects most people when they are young before becoming dormant. Epstein Barr is present in about 90 percent of people. The fourth factor is having Type 2 diabetes. However, researchers involved in other studies indicate that diabetes is only one of several underlying medical conditions that may increase the risk of long COVID.

The group of 209 patients included in the study, ages 18 to 89, who were infected with COVID-19 in 2020 or early 2021m and were seen at Swedish Medical Center or an affiliated clinic. Many were hospitalized for their initial infections. And some were only treated as outpatients.

The most common long COVID symptoms include pain, headaches, fatigue, “brain fog,” shortness of breath, anxiety, depression, fever, chronic cough, and sleep problems. The U.S. National Institutes of Health (NIH) is funding the largest research initiative to study the long-term effects of COVID-19, focusing on long COVID patients.

Boosters Very Effective Against Severe Illness, Hospitalization from Omicron, New Data Finds

During both Delta-predominant surge and current Omicron wave, a third vaccine dose was highly effective at preventing COVID-19–associated emergency department or urgent care visits — by 94 percent (Delta) and 82 percent (Omicron) — and preventing COVID-19–associated hospitalizations 94 percent (Delta) and 90 percent (Omicron), according to new research from the U.S. Centers for Disease Control and Prevention (CDC).

The new CDC study is considered one of the first to focus on the COVID-19 vaccines’ protection against Omicron in the U.S., which represents the vast majority of new cases. The findings reaffirm the importance of booster shots, or third doses, of either the Pfizer-BioNTech or Moderna vaccine to protect against severe illness from the very transmissible variant, which has causes surging hospitalizations nationwide.

Researchers examined recorded associated with 222,772 visits to emergency departments (EDs) and urgent care centers — and 87,904 hospitalizations — reported by 259 hospitals. The data involved adults, aged 18 years and older, across 10 states from August 26, 2021 to January 5, 2022. They were able to discern which adults received either the Pfizer or Moderna vaccines, the primary doses and the third dose (booster).

During the Delta surge, the primary two doses of the vaccine were 86 percent effective against visits to EDs and urgent care centers for COVID-19-related illness. That effectiveness fell to 76 percent after six months. However, a booster raised the effectiveness to 94 percent. During the Omicron surge, two vaccine shots were 81 percent effective. That protection fell to 57 percent in those who were six months out from their second dose — but then jumped to 90 percent after a third dose.

The CDC’s conclusion: “These findings underscore the importance of receiving a third dose of mRNA COVID-19 vaccine to prevent both moderately severe and severe COVID-19, especially while the Omicron variant is the predominant circulating variant and when the effectiveness of 2 doses of mRNA vaccines is significantly reduced against this variant.”

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