An unexpected number of cases of monkeypox have begun appearing in multiple countries since early May 2022, prompting expressions of concern from some public health agencies.
On May 18, CNN wrote that the CDC is "tracking multiple clusters of monkeypox that have been reported within the past two weeks in several countries that don't normally report monkeypox, including Portugal, Spain, and the United Kingdom."
On the same day, Massachusetts public health officials confirmed the first case of monkeypox in the United States, explaining that:
Monkeypox is a rare but potentially serious viral illness that typically begins with flu-like illness and swelling of the lymph nodes and progresses to a rash on the face and body. Most infections last 2-to-4 weeks. In parts of central and west Africa where monkeypox occurs, people can be exposed through bites or scratches from rodents and small mammals, preparing wild game, or having contact with an infected animal or possibly animal products.
According to the CDC:
Transmission of monkeypox virus occurs when a person comes into contact with the virus from an animal, human, or materials contaminated with the virus. The virus enters the body through broken skin (even if not visible), respiratory tract, or the mucous membranes (eyes, nose, or mouth). Animal-to-human transmission may occur by bite or scratch, bush meat preparation, direct contact with body fluids or lesion material, or indirect contact with lesion material, such as through contaminated bedding. Human-to-human transmission is thought to occur primarily through large respiratory droplets. Respiratory droplets generally cannot travel more than a few feet, so prolonged face-to-face contact is required. Other human-to-human methods of transmission include direct contact with body fluids or lesion material, and indirect contact with lesion material, such as through contaminated clothing or linens.
This question seeks to investigate the likely spread of this previously WHO-designated "priority pathogen", and therefore asks:
How many human infections of monkeypox will be estimated to have occurred before 2023, worldwide?
In the last week of December 2023, Metaculus admin and community moderators will review a portion of credible scientific estimates published in the year 2023, of the cumulative total amount of human infections of monkeypox that occurred in the year 2022 in both non-endemic and endemic countries. Admin and community moderators may decide to resolve this question on the basis of the median estimate considered they consider most credible, or decide to resolve this question as the median of all median estimates found by reviewing a portion of credible scientific literature.
If estimates of the total number of worldwide infections are not available at the time of resolution, which may be possible in the scenario in which the global impact of monkeypox is limited, then we will resolve this by using total confirmed+suspected+possible case counts.
Also see this question on the total number of monkeypox deaths in 2022.