(NEXSTAR) – The BA.2 subvariant of omicron, also known as stealth omicron, is quickly gaining ground in the U.S. and has already become the dominant strain globally. Scientists can detect the subvariant by looking at the virus’ genome – but are you able to tell which COVID-19 variant you have based on symptoms?
While there are some major differences between the most common symptoms of delta and omicron, the two types of omicron – BA.1 and BA.2 – don’t appear to cause different symptoms.
The most common symptoms associated with both types of omicron are runny nose, headache, fatigue, sneezing and sore throat, according to the ZOE Covid Study, which has been tracking COVID-19 symptoms in the United Kingdom. Loss of smell and taste is still possible with an omicron infection, but much less common than with the delta variant.
While the symptoms between BA.1 and BA.2 appear to be consistent, there are other differences. “BA.2 differs from BA.1 in its genetic sequence, including some amino acid differences in the spike protein and other proteins,” explains the World Health Organization.
What that means in practice is that BA.2 appears to be more transmissible than BA.1. That explains how it has become the dominant subvariant in such a short amount of time. However, “this difference in transmissibility appears to be much smaller than, for example, the difference between BA.1 and Delta,” the WHO says.
Researchers are still looking at the frequency of reinfection for people who caught the original omicron variant in the winter and become exposed to the new subvariant in the spring. Early studies suggest it’s possible to catch both subvariants, but back-to-back infections are rare given the short amount of time that has lapsed between exposures.
The BA.2 subvariant makes up about 23% of COVID-19 cases in the U.S., according to the CDC’s last estimate. Epidemiologists point out its presence has been doubling about every week.