The US Centers for Disease Control and Prevention recommends polio vaccination boosters for travelers and those who live in countries where the disease is endemic.In July 2022, the US state of New York reported a polio case for the first time in almost a decade in the country. Health officials said the person, an unvaccinated young adult who had not recently travelled abroad, first showed symptoms a month earlier and eventually developed paralysis. The New York State Health Commissioner subsequently attributed this to a vaccine-derived strain of the virus. This strain had also had been detected in wastewater in New York City. As of September 13, 2022 vaccine-derived polio is confirmed to be circulating locally in Rockland County and may be circulating locally in Orange County and may be circulating locally. Western Pacific
In 2000, polio was declared to have been officially eliminated in 37 Western Pacific countries, including China and Australia.Despite eradication ten years earlier, an outbreak was confirmed in China in September 2011, involving a strain common in Pakistan.In September 2019, the Department of Health of the Philippines declared a polio outbreak in the country after a single case in a 3-year-old girl. The outbreak was declared to be ended during June 2021. In December 2019, acute poliomyelitis was confirmed in an infant in Sabah state, Borneo, Malaysia. Subsequently, a further three polio cases were reported, with the last case reported in January 2020. Prior to this, Malaysia had been declared polio-free in 2000. WHO declared an end to the outbreak in September 2021.
The phenomenon can occur over water, when cold arctic air passes over relatively warm water. Intensity and damage
The Fujita scale and the Enhanced Fujita Scale rate tornadoes by damage caused. The Enhanced Fujita (EF) Scale was an update to the older Fujita scale, by expert elicitation, using engineered wind estimates and better damage descriptions. The EF Scale was designed so that a tornado rated on the Fujita scale would receive the same numerical rating, and was implemented starting in the United States in 2007. An EF0 tornado will probably damage trees but not substantial structures, whereas an EF5 tornado can rip buildings off their foundations leaving them bare and even deform large skyscrapers. The similar TORRO scale ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler weather radar data, photogrammetry, and ground swirl patterns (cycloidal marks) may also be analyzed to determine intensity and award a rating. Tornadoes vary in intensity regardless of shape, size, and location, though strong tornadoes are typically larger than weak tornadoes. The association with track length and duration also varies, although longer track tornadoes tend to be stronger. In the case of violent tornadoes, only a small portion of the path is of violent intensity, most of the higher intensity from subvortices.In the United States, 80% of tornadoes are EF0 and EF1 (T0 through T3) tornadoes. The rate of occurrence drops off quickly with increasing strength—less than 1% are violent tornadoes (EF4, T8 or stronger).