COVID-19 Situation Report |
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Editor: Alyson Browett, MPH
Contributors: Clint Haines, MS; Noelle Huhn, MSPH; Amanda Kobokovich, MPH; Christina Potter, MSPH; Matthew Shearer, MPH; Marc Trotochaud, MSPH; and, Rachel A. Vahey, MHS.
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REINFECTION RISK The Omicron BA.5 subvariant has quickly become the most predominant circulating variant in the US due to its ability to evade immunity from either previous infection or vaccination, dashing hopes of a COVID-19 pandemic reprieve. The subvariant is more likely to cause reinfections and is driving a wave of new infections across the country, with official US CDC data showing a daily average of around 100,000 new cases. But experts warn this represents a severe undercount of new cases, as many people are using home tests and not reporting their results to health authorities. Notably, the Walgreens COVID-19 Positivity Tracker shows a weekly 41.6% positivity rate, up nearly 9% over the prior week and the highest since the tracker began.
Prior to the emergence of the Omicron variant and its family of evasive subvariants, reinfections were rare; but now, some countries are seeing reinfections account for a larger proportion of new cases, including the UK, where roughly a quarter of new cases are reinfections. Though many believe BA.5 does not cause more severe disease than other variants, hospitalizations in many countries are rising and evidence suggests that multiple infections can increase the risk of long-term morbidities, including long COVID. Some major U.S. cities, such as New York City and Los Angeles, have reinstated or are considering reinstating mask mandates for indoor spaces, citing concerns over BA.5. Despite these actions, some worry it will be increasingly difficult to convince people to take public health precautions, as funding and mitigation measures have largely been rolled back.
BA.2.75 & BA.5.2.1 SUBVARIANTS Scientists have identified 2 new Omicron subvariants. BA.2.75 was first identified in India—where it makes up at least 25% of sequenced cases and is competing with BA.5 and BA.2—and has been identified in at least 10 other countries, including at least 3 cases in the US. Though BA.2.75 has not yet been named a variant of interest or variant of concern, several virologists are urging continued monitoring of the variant, as mutations in its spike proteins may lead to increased immune escape and an ability to outcompete BA.5. Additionally, officials in Shanghai, China, this week reported a single case of another new subvariant, BA.5.2.1. The subvariant was linked to a case in an overseas traveler and so far has not been identified in other cases.
The European Centre for Disease Prevention and Control (ECDC) and the European Medicines Agency (EMA) this week updated guidance to recommend a second vaccine booster, or fourth dose, for all individuals over age 60 as well as medically vulnerable people in Europe, as COVID-19 cases and hospitalizations increase across the continent. In a joint statement, European Commissioner for Health and Food Safety Stella Kyriakides issued an urgent call for all eligible individuals to get vaccinated and boosted, saying, “There is no time to lose.” Previously, only adults over age 80 were recommended to receive a booster. In the UK, people aged 75 and older, residents in long-term care facilities, and those with weakened immune systems are eligible for second boosters.
ACCESS TO ANTIVIRALS & VACCINES Senior WHO officials are calling on nations to fill immunity gaps through increased vaccination rates and on antiviral manufacturers to improve access to COVID-19 therapeutics. The COVAX initiative has a surplus of vaccines, according to officials, and lower-income countries should focus on vaccinating healthcare workers, older adults, and other vulnerable populations to minimize the risk of COVID-19-related morbidity, including long COVID, and mortality. Additionally, the WHO called specifically on Pfizer to quickly increase access to its COVID-19 oral antiviral medication, Paxlovid, to countries that are struggling to afford or gain access to stocks of the treatment.
The ACT-Accelerator (ACT-A) program—a collaboration among the WHO, governments, and nongovernmental organizations that works to provide equitable access to COVID-19 related tools, including vaccines through COVAX—is set to wind down operations in their current form this fall due to a lack of funding. While ACT-A likely will continue in a scaled-down form—and COVAX, which is housed at Gavi, the Vaccine Alliance is set to continue through 2023—the transition raises questions about how lower-income countries will access adequate supplies of vaccines, diagnostics, and treatments. Notably, a new analysis from the health data group Airfinity estimates that 1.1 billion doses of SARS-CoV-2 vaccines—about 10% of all manufactured doses—have been wasted since late 2020 due to the inequitable global rollout of shots, vaccine hesitancy, and incorrect storage.
PFIZER-BIONTECH VACCINE FOR ADOLESCENTS The US FDA last week expanded full approval of the Pfizer-BioNTech SARS-CoV-2 vaccine to adolescents aged 12 to 15 years. The vaccine, known as Comirnaty, has been available for this age group since the FDA provided emergency use authorization (EUA) in May 2021, and the agency originally approved the vaccine for individuals aged 16 years and older in August 2021. To date, more than 9 million 12-15-year-old children have received the 2-dose primary series. Pfizer and BioNTech indicated they have also filed clinical trial data for approval among this age group with the European Medicines Agency (EMA) and other regulatory agencies around the world.
PULSE OXIMETRY Pulse oximeters are an important tool for measuring the amount of oxygen in the bloodstream and have been widely used in healthcare and home settings during the COVID-19 pandemic. But the devices can overestimate blood oxygen levels in people with dark skin, causing Asian, Black, and Hispanic intensive care unit (ICU) patients to receive less supplemental oxygen than White ICU patients, according to a retrospective cohort study conducted prior to the pandemic and published on July 11 in JAMA Internal Medicine. These differences in performance may contribute to racial and ethnic disparities in care, including among COVID-19 patients. Another recent study showed racial and ethnic differences in pulse oximetry delayed the recognition and treatment of COVID-19 among Black and Hispanic patients.
The US FDA is convening a public meeting of its Medical Devices Advisory Committee later this year to discuss available data and provide guidance to healthcare providers. The agency issued a safety communication about the issue in February 2021 urging patients and providers to be aware of the multiple factors that can affect pulse oximeter accuracy and to consider limitations when using pulse oximeters to make diagnoses and treatment decisions. Some experts are warning of the potential for continued disparate outcomes among racial and ethnic groups as technology becomes more common in healthcare and calling for more diversity in clinical trials.
WASTEWATER SURVEILLANCE Wastewater surveillance can provide first-look data on the spread of SARS-CoV-2 in communities, offering an early warning system for public health officials, healthcare providers, policymakers and others, but low-quality data prohibits estimating prevalence or identifying variants. To address these shortcomings, a team of scientists from Scripps Research Institute and the University of California San Diego (UCSD) developed a new method to increase the amount of viral RNA available to be sequenced in a small wastewater sample and a surveillance tool, called “Freyja,” that uses an algorithm to detect new variants more quickly and reliably, up to 2 weeks before they are identified in clinical sequencing and with enough time to take action. The study describing the work was published July 7 in the journal Nature. The testing technique shortens the time to sequence samples, from weeks to days, which may help to identify and rapidly respond to emerging variants in the future.
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