At a briefing on global health issues today, the head of the World Health Organization (WHO) said there are concerning trends ahead of the Northern Hemisphere winter, including rising deaths in parts of the Middle East and Asia and increased hospitalizations in multiple regions.

WHO Director-General Tedros Adhanom Ghebreyesus, PhD, included the caveat that data are limited, with few countries reporting information. Regarding variants, he said there is currently no dominant one, though EG.5 is on the rise. He said the heavily mutated BA.2.86 variant has been detected in small numbers in only 11 countries, though the WHO continues to monitor developments, especially regarding transmissibility and potential impact.

Over the past day, variant trackers have noted BA.2.86 sequence uploads from more countries, including Australia, and more from countries that already reported sequences, including the United States, involving a sample from Colorado. Delaware yesterday reported its first BA.2.86 case, which involves a Pennsylvania resident who was seen at a Delaware hospital.

By the latest count, at least 84 samples have been uploaded to sequencing databases. Also, scientists have identified the first BA.2.86 sublineage, designated as BA.2.86.1, which has two additional mutations and a synonymous nucleotide mutation.

Tedros added that one of the WHO's biggest worries is the low number of at-risk people who have recently received a dose of COVID-19 vaccine. "Our message is not to wait to get an additional dose if it is recommended for you," he said.

Moderna: Updated vaccine shows strong response against BA.2.86

In related developments, Moderna today announced that a clinical trial with its research assay suggests the updated vaccine, which is under Food and Drug Administration (FDA) review, generates an 8.7-fold increase in neutralizing antibodies in people against BA.2.86.

In a statement, the company's president, Stephen Hoge, MD, said that, taken together with recent findings suggesting a similar response to newer variants EG.5 and FL.1.5.1, the data confirm that the vaccine will continue to be an important tool for protection heading into the fall vaccination season.

Researchers in Sweden report that the risk of getting long COVID after a COVID-19 infection was higher for the wild type, Alpha, and Delta variants compared to Omicron. The study is published in The Journal of Infectious Diseases.

Though prior research has shown that severe COVID-19 is less likely from Omicron infections compared to earlier variants, less is known about how each variant increases the likelihood of developing long COVID, or persistent symptoms lasting 12 or more weeks following acute infections.

The new study is based on cases in Stockholm, Sweden, and includes 3,002 people who received a long-COVID diagnosis any time from 90 to 240 days after first testing positive for SARS-CoV-2. All diagnoses were made after confirmed primary infections with the virus from October 2020 to February 2022.

The investigators classified an infection by variant if confirmed through whole-genome sequencing or if the positive test occurred during the period in which the variant dominated.

No difference among ICU patients

Though more patients were infected during the Omicron phase of the pandemic, only 0.2% in the Omicron cohort were diagnosed as having long COVID, compared with 0.5% in the Delta cohort, 1.0% in the Alpha cohort, and 1.3% in the wild-type cohort.

Compared to Omicron, the adjusted hazard ratio was 3.26 (95% confidence interval [CI], 2.80 to 3.80) for Delta, 5.33 (95% CI, 4.73 to 5.99) for Alpha, and 6.31 (95% CI, 5.64 to 7.06) for the wild-type virus.

Severity of the acute infection, including use of intensive care units (ICUs), was associated with developing long COVID regardless of which variant caused infections. Among those treated in the ICUs for initial infections, there were no significant differences observed among variants for developing long COVID.

A 2023 survey of nearly 2,200 adults in Arizona who had received at least one COVID-19 vaccine dose shows that the most common reason for not receiving a bivalent (two-strain) booster dose was a previous infection, followed by concerns about vaccine side effects, safety, and effectiveness.

University of Arizona researchers surveyed 2,196 recipients of one or more COVID-19 vaccine doses from February 13 to March 29, 2023. The research was published this week in Vaccine.

The authors noted that, as of May 2023, less than 20% of eligible US adults had received a bivalent booster dose, which offers protection against both the wild-type and Omicron SARS-CoV-2 strains for people aged 6 months and older.

Concerns about booster safety, efficacy

Of the 2,196 participants, 74.5% had received a bivalent dose. The 559 respondents who didn't get a booster cited previous COVID-19 infection (39.5%), worries about vaccine side effects (31.5%), thinking that the booster wouldn't provide more protection than previous doses (28.6%), and concerns about booster safety (23.4%) and efficacy (23.1%).

The US Centers of Disease Control and Prevention says of bivalent vaccines, "The current evidence does not support the existence of a safety issue" and says serious side effects are rare.

Effectiveness of vaccines and boosters wane over time, making the development of and adherence to updated vaccine boosters a key public health strategy in protection from the worst SARS-CoV-2–related outcomes.

Participants aged 60 and older were less likely than younger respondents to cite reasons related to a lack of knowledge (odds ratio [OR], 0.24) or logistical concerns (OR, 0.09) about the booster.

Hispanic respondents were more likely than their non-Hispanic peers to indicate concerns about logistics (OR, 2.15), and those with some college or technical education were significantly more likely than college graduates to say that the risks and benefits of the bivalent vaccine were less clear than the reasons for not getting boosted (OR, 2.41).

"Effectiveness of vaccines and boosters wane over time, making the development of and adherence to updated vaccine boosters a key public health strategy in protection from the worst SARS-CoV-2–related outcomes," the researchers wrote. "Implementation remains among the biggest current public health challenges as updated boosters continue to be developed and made available to the public."

• In an outbreak that began in April, Bangladesh is now experiencing its worst dengue activity, the World Health Organization (WHO) director-general said today. Cases are starting to decline in Dhaka, but are increasing in other parts of the country. At a briefing on a host of global health issues, Tedros Adhanom Ghebreyesus, PhD, said the country has reported more than 135,000 cases, along with about 300 deaths.
• Nigeria is experiencing its second diphtheria wave of the year, with 9,000 suspected cases across 17 states, 307 of them fatal, Tedros said at today's briefing. He said the WHO is working with Nigeria's government to improve vaccination, surveillance, and risk communication. "This outbreak and others highlight the need to increase routine vaccination to stop these outbreaks before they start," he said.

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  Uruguay is the latest country in South America to detect H5 avian flu in a sea lion, according to a notification from the World Organization for Animal Health. The juvenile animal was reported with nervous system symptoms on September 2 at a beach near Montevideo, the country's capital. Animal health officials obtained samples, which were positive for H5. The seal died where it was found, and responders conducted a sanitary burial and disinfected the area.