Quick takes: Declassifying COVID-source intel, Cochrane mask review clarification, XBB.1.5 rise in US

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  • In a rare and strong bipartisan vote today, the US House of Representatives voted to declassify US intelligence information about the origins of SARS-CoV-2, the Associated Press and other media outlets reported. The Senate has passed a similar measure, which will now go to Biden's desk for a signature. Two US agencies have concluded that a lab leak was the likely source of the virus in China, the US Department of Energy with low confidence and the Federal Bureau of Investigation with moderate confidence. Other US intelligence agencies, however, have not changed their assessment—also with low confidence— that the source was natural, involving a jump from animals to humans. Last week the World Health Organization pressed China on the origins and also urged countries to share what they know to help nations avoid future pandemics. Scientists have published extensive studies that support a natural source that came from a live-animal market in Wuhan, China, but so far, it's not clear what other information US officials have that would support the lab-leak scenario.
  • The Cochrane Library today issued a statement clarifying its recent review on mask and respirator use in households and healthcare settings, which some people have used to suggest that the measure isn't useful for preventing the spread of COVID-19. In a statement, the group said characterization of the findings is misleading, that the review was inconclusive, and that the primary evidence wasn't able to address whether the intervention itself reduces a person's risk of contracting or spreading the virus.
  • In updated Omicron variant proportion estimates today, the US Centers for Disease Control and Prevention (CDC) said XBB.1.5 makes up nearly 90% of cases, up from 87% the week before. The virus makes up about 80% or more of cases in all US regions. The CDC also added another subvariant to its proportion tracking, XBB.1.5.1, which makes up an estimated 1.6% of cases.

Kids' COVID symptoms—not rates of severe disease—evolved with variants

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Girl in bed fever checkFever and cough were more common among Canadian children infected with the SARS-CoV-2 Delta and Omicron variants than the original, wild-type virus and the Alpha variant, but rates of hospitalization and intensive care unit (ICU) admission stayed the same over time, finds a study published yesterday in JAMA Network Open.

The Pediatric Emergency Research Canada COVID Study Group assessed symptoms among 1,440 COVID-19 patients younger than 18 years seen at 14 Canadian emergency departments (EDs) from August 4, 2020, to February 22, 2022. Research assistants telephoned patients' caregivers a median of 2 days after their ED visit. Median age was 2.0 years.

Omicron patients most likely to be treated

Whole-genome sequencing was conducted for 26.9% of patients, identifying Alpha (40.7%), Delta (45.6%), and Omicron (11.9%), in addition to one Beta and six Gamma cases; the remainder of the tests were inconclusive.

Children with Alpha infections reported the fewest COVID-19 symptoms (195 of 237 [82.3%]), while Omicron patients reported the most (434 of 468 [92.7%]). Relative to the wild-type virus, Omicron and Delta were more strongly tied to fever (odds ratios [ORs], 2.00 and 1.93, respectively) and cough (ORs, 1.42 and 1.57).

Upper respiratory tract symptoms were most common with Delta (OR, 1.96), while lower respiratory tract and systemic symptoms were tied to Omicron (ORs, 1.42 and 1.77, respectively).

Compared with Delta patients, Omicron patients were more likely to undergo chest radiography (difference, 9.7%), receive intravenous fluids (difference, 5.6%) or corticosteroids (difference, 7.9%), and return to the ED (difference, 8.8%). The proportions of patients hospitalized or admitted to an ICU did not differ among variants.

The proportions of infected children experiencing undesirable outcomes in our study remained stable.

Patients with Delta infections were most often also infected with other respiratory viruses (40.0%). Of the 69.3% of parents asked about their child's COVID-19 vaccination status, 8.0% said they had received at least one dose, 81.8% were unvaccinated, and 10.2% were unsure.

"Although the characteristics of presenting symptoms changed as the SARS-CoV-2 virus evolved, unlike in adults where mortality declined in subsequent waves, the proportions of infected children experiencing undesirable outcomes in our study remained stable," the authors wrote.

CDC recommends hepatitis B screening for all adults

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The US Centers for Disease Control and Prevention (CDC) today recommended universal hepatitis B (HBV) screening for adults, spelling out the details and background behind its decision in the latest issue of Morbidity and Mortality Weekly Report.

The CDC said people with chronic hepatitis B infection are at increased risk for liver cancer and cirrhosis and are 70% to 85% more likely to die prematurely than uninfected people. It said about 580,000 to 2.4 million people have chronic HBV infection, two thirds of whom may not be aware of their infections.

Though the HBV vaccine is highly effective, about 70% of adults are unvaccinated. Treatments are available but aren't curative, but they can help reduce morbidity and mortality.

The updated screening recommendations call for all adults to be screened with three lab tests at least once during a lifetime. The CDC's recommendations also expand risk-based recommendations to include anyone who has had high-isk exposures, including people who are or were incarcerated, those with previous sexually transmitted disease, those with multiple sexual partners, and those with a history of hepatitis C infection.

The CDC said anyone who requests HBV screening should receive it, regardless of risk, because people may be reluctant to reveal risks that carry stigma.

Singapore study highlights patient expectations for antibiotics

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A study conducted in four Indonesian emergency departments (EDs) found that patients who expected antibiotics for a respiratory infection were more likely to receive them, even during the COVID-19 pandemic, researchers reported today in the Journal of Global Antimicrobial Resistance.

The cross-sectional study examined adult patients with uncomplicated upper respiratory tract infections (URTIs) who were treated in one of the four EDs from March 2021 to March 2022. The patients were asked to complete a survey questionnaire post-consultation that asked about their demographics, health status, health-seeking behavior, and their expectations, knowledge, and attitudes on the use of antibiotics. Using multivariable logistics regression models, the researchers assessed the factors associated with the expectation for receipt of antibiotics.

Of the 681 patients recruited for the study, 31% were expecting antibiotics and 8.7%—whether they expected them or not—received antibiotics during the ED visit. Of the patients expecting antibiotics, 15.6% received them. Patients expecting antibiotics during their ED visit were more than 10 times likelier (adjusted odds ratio [aOR], 10.64, 95% confidence interval [CI], 5.34 to 21.17) to receive antibiotics. Patients who received antibiotics during a prior consultation were nearly three times as likely (aOR, 2.97, 95% CI 1.26 to 7.00) to receive antibiotics compared with patients with no prior consultation. 

Our findings highlighted an opportunity for leveraging the COVID-19 mass communication channels to educate the public on the non-necessity of antibiotics for URTI.

Patients who received antibiotics during a prior consultation were more than six times likelier (aOR, 6.56; 95% CI, 3.30 to 13.11) to expect antibiotics compared with those with no prior consultation, while patients with poor (aOR, 2.16; 95% CI, 1.26 to 3.68) to moderate (aOR, 2.26; 95% CI, 1.33 to 3.84) knowledge of antibiotics and antimicrobial resistance (AMR) were twice as likely to expect antibiotics compared with patients with good knowledge of antibiotics.

The top reasons for expecting antibiotics were the perceived severity of the illness and the effectiveness of antibiotics in speeding up recovery.

"Our findings highlighted an opportunity for leveraging the COVID-19 mass communication channels to educate the public on the non-necessity of antibiotics for URTI to address the problem of antibiotic misuse and AMR," the study authors wrote.

Five countries report more vaccine-derived polio cases

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In its weekly update yesterday, the Global Polio Eradication Initiative (GPEI) reported more polio cases from five countries, four in Africa and one in Israel that was previously reported by the country's health officials.

In Africa, Chad reported one circulating vaccine-derived poliovirus type 2 (cVDPV2) case in Salamat, which is included with its 2022 total that is now at 44 cases. The Democratic Republic of the Congo reported 17 cases from six provinces, bringing its 2022 total to 312. It also reported 10 more circulating vaccine-derived poliovirus type 1 (cVDPV1) cases, boosting its 2022 total to 115.

Madagascar reported 5 more cVDPV1 cases, the first such cases of 2023. In 2022, it reported 14 cases. Nigeria reported 1 more cVDPV2 case, in Lagos, raising its 2022 total to 48.

The GPEI also reported the case from Israel, the earlier-reported patient from North province, marking its first case of 2023. The investigation has turned up three positive cases in the patient's asymptomatic contacts.

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