How Is the More Contagious 'Stealth Omicron' Different?

[Asia Economy Reporter Hyun-ui Cho] The stealth Omicron (BA.2), a subvariant of the COVID-19 Omicron variant (BA.1), has been identified in at least 40 countries.

According to the Wall Street Journal on the 28th (local time), cases of stealth Omicron infections have been reported in at least 40 countries including South Korea, Denmark, the United States, the United Kingdom, and Sweden. Here is a summary of related questions.

[Image source=Yonhap News]

- How is it different from the existing Omicron?

▲ BA.2 is commonly called 'stealth Omicron' because it is not easily distinguishable from other variants in PCR (polymerase chain reaction) tests. It is still unclear whether its mechanism is substantially different from the existing Omicron.

However, a study released at the end of last month showed that stealth Omicron has 28 mutations different from the existing Omicron. The existing Omicron has more than 50 mutations.

- Is it more infectious?

▲ Since stealth Omicron has already become the dominant strain in Denmark, experts believe it is more infectious than the existing Omicron. Professor Hioshi Nishiura of Kyoto University in Japan analyzed that stealth Omicron’s transmissibility is 18% higher than that of the existing Omicron.

Professor Tom Peacock of Imperial College London also said, "The steady increase in infection cases in several countries is evidence that stealth Omicron transmits somewhat better than the existing Omicron."

- Is there a higher risk of developing severe symptoms upon infection?

▲ It has not yet been confirmed how stealth Omicron affects severity. However, early research in Denmark showed that the hospitalization rate of stealth Omicron is not significantly different from that of the existing Omicron.

The U.S. Centers for Disease Control and Prevention (CDC) also explained, "Although stealth Omicron is spreading in several countries, it accounts for a very small proportion," and "there is no evidence yet that stealth Omicron is more severe than the existing Omicron."

- Is there vaccine effectiveness?

▲ It is still too early to judge, but it appears to be similar to the existing Omicron. Danish health authorities believe that existing vaccines are effective in preventing severe risk from stealth Omicron as well.

- In which countries has it been identified?

▲ Infection cases have been reported in at least 40 countries including Denmark, the United States, the United Kingdom, Sweden, Norway, and South Africa. It has also been confirmed in many Asian regions such as South Korea, Japan, India, Taiwan, Hong Kong, Singapore, and the Philippines through imported cases.

This content was produced with the assistance of AI translation services.