According to foreign media reports, the COVID-19 variant XBB.1.16 is spreading in many countries. XBB.1.16 is a recombinant strain of COVID-19 Omikron, belonging to the XBB family, and is a mixture of two different BA.2 strains. On January 9th, it was first reported and on March 22nd, it was designated as a "mutated strain that needs to be monitored" by the World Health Organization (WHO). In the folk, it is named "Big Horn Star". So far, the majority of cases caused by 'Arcturus' have occurred in India, with mild symptoms being the main cause. It has also been discovered in 32 other countries, including Singapore, the United States, the United Kingdom, and Australia. On April 17th, the World Health Organization listed XBB.1.16 as a "noteworthy variant (VOI)". Ali Mokdad, a professor of global hygiene at the University of Washington in the United States, believes that it is still too early to predict how XBB.1.16 will develop. But so far, the situation has been reassuring, he said, without seeing an increase in the number of hospitalizations or any indicators that have worried doctors and experts. Is it more infectious? Natalie Thornberg of the US Centers for Disease Control and Prevention (CDC) said that XBB. 1.16 has only a few mutations on the spike protein of COVID-19 compared with its predecessor mutant, which is less than dozens of mutations of the original Omicron mutant in the early stage of the pandemic. According to CDC data, as of April 22, XBB. 1.16 still accounted for slightly less than 10% of newly diagnosed cases of COVID-19 infection, but the proportion has been rising steadily in recent weeks. Mokdad stated that XBB.1.16 is gradually replacing the previously dominant variant XBB.1.5 in the United States. The increase in its transmissibility seems to be due to the immune escape ability of this sub variant, but it is not fatal. Peter Qin Hong, a professor of infectious diseases at the University of California, San Francisco, said that so far, there is not much difference between XBB.1.16 and XBB.1.5, except for the increase in transmission. This means that there will not be much difference in terms of its pathogenicity and the effectiveness of the vaccine against it. Capitol Hill website reported that although there are more and more sub variant classifications, WHO believes that "Arcturus" has no "additional public health risk" compared with XBB. 1.5 and other descendants of Omicron. After XBB.1.16 was declared VOI, the World Health Organization stated in its preliminary risk assessment that based on existing evidence, its global risk assessment is relatively low. WHO officials have observed that certain characteristics of 'Arcturus' differ from other mutant strains, making it more effective in evading immune responses. However, there have been no reports of changes in the severity of the disease in countries or regions where the virus is transmitted. What are the symptoms? Dr. Mike Ryan, Executive Director of the WHO Health Emergency Program, said that XBB.1.16 does not seem to be as infectious as the early Omicron variant. To my knowledge, we have not seen any changes in symptoms or severity related to this mutant strain. The National Broadcasting Corporation of the United States reported that XBB.1.16 infection can lead to