The previous outbreaks in Hong Kong and South Korea all pointed to the Omicron subtype BA.2. Even the CDC in the United States found that the number of cases of BA.2 increased significantly, which made the BA. Many people worry about whether BA.2 will cause the next wave of the epidemic. Huang Gaobin, deputy director of the Infection Control Center of the Hospital Affiliated to China Medical University, said: “Don’t be too nervous in the face of BA.2, it seems to be more infectious at present. Many of its features are very similar to BA.1.”
What is BA.2?
Omicron types include BA.1, BA.2, BA.3. In short, BA.2 is a subtype of Omicron, while Omicron in the past mainly refers to BA.1 accounting for the world’s most popular However, with the evolution of the epidemic, the number of cases of BA.2 has gradually increased, even surpassing that of BA.1.
BA.2 does have obvious mutation in the receptor binding position, which is different from BA.1, but there is no evidence of toxicity in toxicity.
Are the symptoms of BA.2 different? High transmission power?
From the CDC surveillance in the United States, it was found that the severity of the disease caused by BA.2 and BA.1 was not much different, and the main symptoms after infection were headache, sore throat, sneezing, runny nose, and body pain.
But the US National Library of Medicine notes that BA.2 has two other, more distinct symptoms: Dizziness, fatigue People with Omicron experienced symptoms for about two days less than those infected with Delta, with slightly different symptoms, with more patients reporting a runny nose, sore throat, sneezing and headache.
While Omicron also infects the lungs, the virus seems to prefer to stay in the upper respiratory tract, meaning that infected people tend to cough more and produce more phlegm. One of the reasons Omicron has become so easy to spread.
In particular, the transmission power of BA.2 is indeed about 30% higher than that of BA.1. Many characteristics of BA.2 are very similar to BA.1. The US CDC report emphasizes that although the transmission power of BA.2 is a little stronger , there will not be a sharp increase in cases like Omicron when it came out, and the clinical symptoms are not worse than BA.1.
Can vaccines protect against BA.2? The recent serious epidemic in Hong Kong makes people think that the vaccine has failed?
Hong Kong is mainly a large number of infections among the elderly. They may not have been vaccinated, or they may have been vaccinated by Sinovac. However, Sinovac vaccine data shows that compared with other WHO-certified vaccines, the human body can produce antibodies and immunity. The reaction is weak, and the protection may be poor after a long time. ”
After the first dose, the ethnic group should take the second dose. The two doses are our basic doses, which allow the body to develop immunity and memory. The third dose depends on the time interval between the second doses. If there is a difference More than six months, try to play as soon as possible to increase the body’s memory.
BA.2 may be “reinfected”?
Due to the concern of repeated infection due to BA.2 antigen changes, a previous study by the Danish CDC found that Delta and BA.1 recovered patients were still at risk of re-infection with BA.2, and found that 263 cases of re-infection were found. Among the patients infected with new coronary pneumonia, 190 of them were caused by BA.2.
Studies have shown that BA.1 survivors may be re-infected with BA.2, but this is very rare. If you have been infected with BA.1, even if the symptoms after repeated infection are relatively mild, it may be Mild or even asymptomatic. Don’t worry too much about BA.2, consider him a kind of Omicron.