Two people had connections to camels, but the exposure source is still unknown for two of the patients.
MERS-CoV antibody reactivity was identified in 7 of 48 camel-slaughterhouse workers (15%).
Groups announced new clinical trials and more support for universal flu, MERS, and mpox vaccines.
Prioritized COVID tracking and effects from COVID control measures likely contributed to a drop in MERS cases, but the threat remains, the WHO said.
The source of the virus isn't clear, and genetic analysis is underway to look for clues or changes and to help with risk assessment.
The findings could help in the structure-based design of pan-coronavirus vaccines and therapies, the authors say.
Scientists find 4 species of coronaviruses, including 2 novel ones, in UK bats, but experts say they pose little risk to people.
The man didn't have direct contact with camels, though camel racing exercises were held near his house before he fell ill.
Three of the patients had recent contact with camels.
"What's needed are vaccines that are durable, with a wide breadth of protection."