COVID-19 Situation Report
Editor: Alyson Browett, MPH

Contributors: Clint Haines, MS; Natasha Kaushal, MSPH; Amanda Kobokovich, MPH; Christina Potter, MSPH; Matthew Shearer, MPH; Marc Trotochaud, MSPH; and, Rachel A. Vahey, MHS.
US CDC MASK GUIDANCE The US CDC issued new guidance on February 25 on when US residents should consider wearing masks to lower the risk of SARS-CoV-2 transmission. The strategy moves beyond using the number of new COVID-19 cases and percentage of positive test results over the previous week as benchmarks and instead considers 3 different metrics—new COVID-19 admissions per 100,000 population in the past 7 days, the percent of staffed inpatient beds occupied by COVID-19 patients*, and total new COVID-19 cases per 100,000 population in the past 7 days—to determine US counties’ COVID-19 community level. Using that data, community level is classified as low (green), medium (yellow), or high (orange), and the CDC released an interactive map allowing people to search visually or by county name to determine counties’ COVID-19 community level. The agency advises universal indoor masking, including in schools, only in counties with a “high” COVID-19 community level. In medium-risk communities, the agency recommends those who are at an increased risk of severe disease ask their doctor about wearing a mask. Others in medium- and low-risk communities may choose whether or not to wear a mask, regardless of vaccination status. However, the agency continues to recommend vaccination and boosters for all eligible people, and anyone with symptoms, a positive SARS-CoV-2 test, or exposure to someone with COVID-19 should wear a mask in public. The new strategy does not apply to travelers on airplanes, trains, and buses and at airports and train stations. The CDC plans to soon revisit those requirements, which are set to expire on March 18.

Many public health experts agreed the changes make sense, with some saying masks should become a normalized courtesy, where people wear them out of respect if they have symptoms. Others, including individuals made vulnerable to severe COVID-19 because of compromised immune systems or other conditions, feel left behind under the new guidance. The administration of US President Joe Biden announced last week it is taking steps to make masks and tests more accessible to people with certain disabilities, but some advocates say the efforts have been slow to materialize and viewed as an afterthought. The new CDC mask recommendations, as well as the waning number of new COVID-19 cases nationwide, also led some experts to warn that, while hopeful, these conditions do not signal the end of the pandemic. According to a recent poll from the Kaiser Family Foundation, most adults disagree about what a return to normal means and when it should occur. And while most agree that the worst of the pandemic is over, there remains uncertainty about the future, with 17% of adults saying the worst is yet to come. With mask mandates and other pandemic-related restrictions being dropped across the country, President Biden is expected to address the state of the pandemic in his first State of the Union address this evening but stop short of declaring victory.
*Hospitalizations are counted as all patients with COVID-19, regardless of reason for admission.

VACCINE EFFECTIVENESS Data compiled by the New York State Department of Health indicates that the smaller Pfizer-BioNTech SARS-CoV-2 vaccine is less effective at preventing infection and COVID-19-related hospitalization in children ages 5 to 11 years compared with older children ages 12 to 17. The findings, which are not yet peer-reviewed, showed quicker declines in vaccine effectiveness (VE) in the younger cohort. VE against cases declined from 66% to 12% in the 5- to 11-year-old cohort, while VE in the 12- to 17-year-old group declined from 66% to 51% between December 13, 2021, and January 30, 2022. A similar trend was shown in VE against hospitalizations over the study period: 100% down to 48% among the youngest cohort and 85% to 73% in the young adolescent group. The authors note that dosing could be a factor in the VE decline, as children ages 5 to 11 receive smaller doses of vaccine. The adult dose, also given to those aged 12 to 17 years, is a 2-dose regimen of 30 µg, while those aged 5 to 11 receive 2 10μg doses in the trial. In clinical trials, children ages 6 months to <5 years are receiving even lower doses of the Pfizer-BioNTech vaccine, 2 or 3 shots of 3μg. The US FDA and the companies recently delayed review of an application for authorization among this group to await trial results of a 3-dose regimen, expected in April, after 2 doses did not produce antibody levels in 2- to 4-year-olds on par with people aged 16 to 25. The Pfizer-BioNTech vaccine is currently the only one authorized in the US for use among children ages 5 to 11.

Results of a test-negative case-control study evaluating Moderna’s vaccine effectiveness against the Delta and Omicron variants found the vaccine to be more effective against infection with the Delta variant but highly protective against hospitalizations for both variants. Three-dose (2-dose primary series plus a booster dose) VE against hospitalization with Delta and Omicron was >99% across the entire study population. Evaluated at 14-60 days and >60 days, 3-dose VE against infection showed high, durable immunity against Delta, with VE declining slightly from 93.7% to 86.0%, but lower effectiveness against Omicron, with VE falling from 71.6% to 47.4%. In immunocompromised individuals, the 3-dose VE was 29.4% against Omicron. 

The study aligns with US CDC findings that vaccine protection against Omicron was weaker compared to other variants, but vaccination continued to provide protection against hospitalization during the Omicron surge. The likelihood of unvaccinated people being hospitalized was 15 times greater than that of fully vaccinated people during earlier variants and fell to about 7 times the risk with the Omicron variant. Despite waning effectiveness, vaccines continue to protect against death amid the Omicron surge. At the end of December 2021, unvaccinated people were 10 times more likely to die of COVID-19 than fully vaccinated individuals. 

ASIA The number of new COVID-19 cases continues to drop globally except in Asia, where the number of confirmed cases increased nearly 32% the week ending February 21. In Hong Kong, an Omicron variant-fueled surge has overwhelmed the city’s “dynamic zero” strategy—the same as mainland China’s—raising panic and fear among residents who emptied grocery store shelves over the weekend. The COVID-19 fatality rate in Hong Kong is now the highest in the developed world, leaving the healthcare system overloaded with patients and mortuaries at capacity. Older residents, who are most at risk, remain the least vaccinated. Leaders have implemented vaccine passports, mask mandates, and mandatory mass SARS-CoV-2 testing—3 tests for each resident over a 9-day period—and many are concerned lockdowns could soon follow. Some expatriate residents are leaving the city in order to avoid testing and potential lockdowns and keep their children in school, after the city announced school closures this month. 

The number of new COVID-19 cases and related deaths also are soaring in South Korea, with the nation setting a single-day mortality record on February 28 with 114 deaths. Notably, the nation dropped its “anti-epidemic pass” mandate today, which required people to show proof of vaccination or negative test to enter any indoor area, in order to allow more healthcare workers to move freely to care for the nearly 800,000 patients with mild-to-moderate COVID-19 who are isolating at home to preserve hospital beds. Some say the new strategy to monitor patients at home felt like “home abandonment,” with government-sponsored shipments of medical supplies—such as thermometers, pulse oximeters, and other supplies—failing to arrive on time. 

Across the border in North Korea, the government continues to claim it has recorded no COVID-19 cases since the beginning of the pandemic. Last week, an independent UN human rights investigator called on the international community to provide North Korea with at least 60 million doses of SARS-CoV-2 vaccines in order to ward off a humanitarian crisis and persuade the country to ease lockdowns that have left much of its population at risk of starvation. Notably, the COVAX initiative recently scaled back the number of vaccine doses allocated to the country since the government has failed to arrange for any deliveries and previously rejected planned shipments.

CARIBBEAN While the number of new COVID-19 cases are declining across the Americas, the Caribbean is falling behind, the Pan American Health Organization (PAHO) warned last week. In the region, 10 out of the 13 countries and territories that have yet to reach the WHO goal of vaccinating 40% of their populations are in the Caribbean. Experts caution against interpreting declines in case numbers as evidence that the virus is disappearing, as some locations continue to experience outbreaks. Although barriers to vaccination persist in the Caribbean—including vaccine hesitancy, lack of rural vaccination centers, insufficient staff, and limited cold-chain infrastructure—PAHO called on governments and healthcare workers to use available tools to “to turn the tide on vaccinations” by providing communities with more information, education, and accessible vaccination opportunities. 

CHILDREN WHO LOST CAREGIVERS Globally, more than 5.2 million children lost a parent or caregiver during the first 19 months of the COVID-19 pandemic, according to a study published in The Lancet Child & Adolescent Health. A collective of international researchers and experts from various health organizations and universities collected data from more than 20 countries. The research estimates the number of children experiencing COVID-19-associated orphanhood or caregiver death increased 90% from April 30 to October 31, 2021, from 2,737,300 to 5,200,300. Paternal orphans represented 76.5% of the orphaned children, compared to 23.5% who lost their mother. Beyond the tragic numbers, the study warns that children who lose a parent are at greater risk of poverty, sexual abuse, mental challenges, and severe stress. 

PLANT-BASED VACCINE After authorizing Novavax’s protein-based SARS-CoV-2 vaccine Nuvaxovid for adults aged 18 and older on February 17, Canada’s drug regulator last week cleared a second non-mRNA vaccine against COVID-19, authorizing Medicago’s Covifenz vaccine for adults ages 18 to 64. The 2-dose vaccine uses plant-based, non-infectious virus-like particles (VLP) of spike protein from the original SARS-CoV-2 strain, as well as an adjuvant from GlaxoSmithKline to boost immune response. Quebec-based Medicago has agreed to supply up to 76 million vaccine doses to the Canadian government, the first shipments of which are expected in May. In a study of 24,000 adults, the overall vaccine efficacy rate was 71% against all SARS-CoV-2 variants, although the clinical trial was performed prior to the emergence of the Omicron variant of concern. The authorization represents the first of a vaccine manufactured using plant-based technologies, and public health officials are hopeful Covifenz and Nuvaxovid will provide options to people who are not willing to receive an mRNA-based vaccine. However, since 81% of the total Canadian population is fully vaccinated, many of the vaccine doses likely will be shipped overseas. Health Canada has authorized the use of 6 SARS-CoV-2 vaccines.

SARS-COV-2 ORIGIN In 3 preprint studies posted online last week, scientists provide additional evidence that the COVID-19 pandemic originated in a Wuhan, China, market due to a zoonotic viral spillover event. The studies, posted on February 25 and 26, have not yet been peer-reviewed or published in a professional journal. The first study presents analyses of 1,380 samples collected in early 2020 from the Huanan Seafood Market (HSM), the surrounding environment, and animals within the market. Researchers detected SARS-CoV-2 in the stalls of the HSM western zone and other environmental samples, but they did not detect the virus in samples taken from 18 animal species present at the market, including some stray animals. A second study uses geospatial analyses to show that the earliest COVID-19 cases diagnosed in December 2019 were located close to and centered on the market and that environmental samples positive for SARS-CoV-2 were strongly associated with vendors selling live animals. A third study suggests that SARS-CoV-2 arose in humans after at least 2 separate cross-species transmission events in late 2019, possibly from live animals sold at the HSM. 

Many scientists agree that the preponderance of evidence, included in these studies and others, supports a zoonotic origin story of SARS-CoV-2 instead of an accidental laboratory leak. However, none of the studies provide definitive evidence about what animal species might have hosted the virus prior to it jumping to humans. Nor do the studies rule out that the HSM could have simply served as the location of a large amplifying event in which an infected person transmitted the virus to many others. Researchers around the world continue to analyze available evidence, but without additional samples from early human cases and animals, the world may never know the true origin of the novel coronavirus that has so far killed at least 6 million people worldwide in just over 2 years.