The British health and safety agency issued a statement on the 10th that more virus strains were detected after the "vaccine derived" type 2 poliovirus was detected in the sewage samples in London earlier this year. The British government's scientific advisory body on immunization recommended that all children aged 1 to 9 in London be provided with polio vaccine booster. The British health and safety agency said in the communique that after the discovery of type 2 poliovirus in the sewage samples from the Beckton sewage treatment plant in London from February to may, the agency and the British medicines and health products administration have confirmed at least one positive poliovirus sample in further upstream sampling, and viruses with lower concentrations have also been found in other parts of London. The detected level of poliovirus and the high genetic diversity among poliovirus type 2 strains indicate that virus transmission has exceeded the range of a few closely related individuals. The agency said that among the 19 sewage samples collected in London from February 8 to July 5 this year, 116 strains of poliovirus type 2 had been found, and a few of them had mutated into poliovirus type 2 that can be classified as "vaccine derived". This virus is "more worrying" and may cause paralysis of unvaccinated individuals in rare cases. The Joint Committee on vaccination and immunization, the scientific advisory body of the British government on immunization, recommended that targeted booster injections of inactivated polio vaccine be provided to all children aged 1 to 9 in London. Vanessa Saliba, an epidemiologic consultant of the health and Safety Bureau, said in a statement that currently there are no polio cases reported, and the risk is very low for most people who have been fully vaccinated. However, in London, the vaccination rate in the area where the virus is currently spreading is the lowest, and people who have not been fully vaccinated face greater risks. The health and safety bureau is continuing to strengthen sewage monitoring to assess the extent of virus transmission. It is also working closely with the health agencies in the United States and Israel and the World Health Organization to investigate the relationship between the virus found in London and the recent polio incidents in these two countries. The state of New York in the United States reported a polio case in July this year, which is the first case found in the United States in the past 10 years. The UK reported the last case of polio in 1984. Polio, commonly known as polio, is an acute infectious disease caused by poliovirus, mainly affecting children under 5 years old. There is no cure for poliomyelitis at present, and vaccination is still the most economical and effective way to prevent and control related diseases. (news agency)