CDC: More than 2 dozen hikers sickened with norovirus on Pacific Crest Trail in 2022

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pacific trail — Peter Stevens / Flickr cc

Today in Morbidity and Mortality Weekly Report authors published accounts of at least 27 cases of acute gastroenteritis (AGE) reported among hikers of the Pacific Crest Trail in August and September of 2022, suggesting a possible norovirus outbreak that sickened hikers who shared latrines and a cabin.

Though only 27 hikers responded to a REDCap survey posted on a Facebook group popular with Washington Pacific Crest Trail hikers in September of 2022 and reported illness, social media was littered with numerous accounts of AGE among Washington-based hikers throughout 2022.

Among survey responses from the 27 ill Pacific Crest Trail hikers, investigators collected symptoms, locations, and contact details. Twenty (74%) survey respondents reported an illness of short duration (median of 2.5 days), and 17 (22%) reported vomiting and diarrhea.

"Twenty-one (95%) survey respondents who reported an onset date noted that they became ill within a 73-mile stretch of the Washington Pacific Crest Trail; this suggested the potential for environmental exposure," the authors wrote.

A difficult environment for controlling norovirus

Environmental sampling of two latrines, a trail cabin, and water stations conducted in October showed no Escherichia Coli or norovirus contamination, but "…epidemiologic links all supported the conclusion that the outbreak was primarily caused by norovirus, and that exposure to contaminated surfaces within the cabin and VIP latrines likely amplified transmission.”

Hiking trails are a difficult environment to control for norovirus, the authors said, noting a lack of easily accessible clean water and soap for hand washing. Alcohol-based hand sanitizers, though common on camp sites, are not effective against norovirus.

Smart people first in line for COVID-19 vaccines, study suggests

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Mary Van Beusekom, MS

Woman getting vaccinated against COVID-19 — New York National Guard / Flickr cc

Intelligent people get their COVID-19 vaccines much faster, suggests a study of more than 750,000 people in Sweden published in the Journal of Health Economics.

Uppsala University researchers assessed the relationship between cognitive ability and prompt COVID-19 vaccination among 750,000 men and 3,000 women who registered for military service in Sweden from 1979 to 1997. The team used intelligence-test data from the Swedish Military Archives.

In Uppsala, after priority groups received their COVID-19 vaccinations, the government made vaccination appointments for all residents aged 50 to 59 years.

"Most Western countries wanted their populations to be vaccinated as soon as possible," coauthor Oscar Erixon, PhD, said in an Uppsala University news release. "We wanted to investigate whether there was a link to cognitive ability or whether other factors caused the differences and led to people hesitating to get vaccinated."

140-day difference between groups

A total of 80% of the most intelligent people were vaccinated within 40 days of vaccine availability, while it took 180 days for those with the lowest cognitive ability to reach that level. The results, the researchers said, suggest that the complexity of the vaccination decision may make it difficult for people with lower cognitive abilities to understand the benefits of vaccination.

"If we are to have equal care for all, we need to take into account the different ways people absorb information," lead author Mikael Elinder, PhD, said in the release.

If we are to have equal care for all, we need to take into account the different ways people absorb information.

Mikael Elinder, PhD

Coauthor Mattias Ohman, PhD, said that making vaccination appointments for people accelerated uptake in both groups. "Logging on to a website, finding an appointment, booking it, going there and getting vaccinated may have been too many steps for some people," he said.

Erixon said some disparities in vaccination behavior can be addressed through better-designed vaccination campaigns. "As it is known that the group with lower cognitive ability was also hit harder by COVID-19, such a measure is likely to contribute to more equal health outcomes," he said. "Faster vaccination rates are also likely to help bring an end to the pandemic more effectively."

Quick takes: Global flu stays low, BARDA award for H5N8 flu vaccine, polio in Africa

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Lisa Schnirring

Global flu activity remains low, with a few parts of the world experiencing sustained or rising activity, the World Health Organization (WHO) said in its latest update, which covers roughly the first half of August. In South Asia, detections increased in Bangladesh, Bhutan, and Nepal. In South East Asia, flu remained elevated in countries including Malaysia, Singapore, and Thailand. In East Asia, Hong Kong's flu activity rose slightly above the epidemic threshold, mainly due to H3N2. In the Americas, flu activity remained above baseline in Costa Rica, El Salvador, Nicaragua, and Mexico. Of respiratory samples that tested positive for flu at national flu labs, 70.6% were influenza A, and of subtyped samples, 62% were H3N2.
CSL Seqirus last week announced an award from the Biomedical Advanced Research and Development Authority (BARDA), part of the US Department of Health and Human Services (HHS), to deliver one bulk lot of H5N8 antigen to the US government as part of pandemic preparedness. The award is the third for Seqirus following ongoing outbreaks of highly pathogenic avian influenza. Earlier awards were for a H5N8 vaccine virus seed and a H5N8 vaccine candidate for a phase 2 study, which was produced at the company's facility in Holly Springs, North Carolina. H5N8 viruses belonging to the current 2.3.4.4b clade have caused outbreaks in poultry, with a few human cases reported from Russia in 2021.
Four countries in Africa reported more polio cases this week, all involving vaccine-derived strains, according to the latest weekly update from the Global Polio Eradication Initiative (GPEI). The Democratic Republic of the Congo (DRC) reported one more infection involving circulating vaccine-derived poliovirus type 2 (cVDPV2), bringing its total for the year to 82. Kenya reported two more cVDPV2 cases, raising its total to five. Mali reported three cases involving the same type from three different regions, putting its total at six for the year. And Tanzania reported one case from Rukwa, its second of the year.