A new sub-variant of Omicron, called BA.2, has made its appearance in the new year and has started to cause some concern. How justified are they and what do we know about it so far?
Here are eight questions and answers based on an article by New Scientist.
What is BA.2?
Basically it's just another flavor of the Omicron variant that's actually been around since the beginning of the latter's appearance. The term Omicron encompasses a whole family of sub-variations that suddenly appeared in November 2021. Most cases of Omicron worldwide have been caused by sub-variant AB.1; AB.2 has 32 identical mutations to AB.1, but 28 different ones. The first diagnosed case of AB.2 was discovered in a sample from South Africa on 11 November last year.
And why are we now hearing about this AB.2 after so long?
In several countries, including Britain, Germany, Denmark and India, the proportion of cases of AB.2 in the total has increased rapidly. It seems that AB.2 is gradually replacing BA.1, suggesting that it is more contagious than the latter.
Should I be concerned about BA.2?
Yes, if you are unvaccinated and have not been infected by Omicron in the meantime. In that case, if you are infected, even if you do not become seriously ill, you can set off a chain of infections, some of which may lead to death. But if you are fully vaccinated and have a booster dose, or if you were previously infected with Omicron, then these risks are much lower.
I can be infected with BA.2, if I have already had Omicron?
We don't know that yet, but many scientists expect that if people have recently been infected with BA.1, then they are unlikely to be infected with BA.2, especially if they have already been vaccinated. This does not mean that it is impossible for a new infection to occur in the same person, but it is something with a low probability. The antibodies that someone has acquired after being infected with BA.1 will logically work well against BA.2, certainly much better than antibodies after a previous infection with a Delta variant.
What if I have been vaccinated but not infected with Omicron?
Existing vaccines actually provide even better protection against BA.2 than against BA.1. According to the UK Health Protection Agency, three doses of vaccine (two weeks after the third dose) are 70% effective in preventing symptomatic disease from BA.2, and 63% effective against BA.1. The corresponding efficacies after two doses (25 weeks after the second dose) are 13% against BA.2 and only 9% against BA.1. These numbers are for all vaccines combined.
Is BA.2 going to cause a new wave of cases worldwide?
Hopefully not, although BA.2 may prolong the current waves of Omicron in many countries. It is hopeful that in South Africa, where the Omicron wave has almost died out, that there are no signs of a resurgence, even though the country has a high rate of cases of BA.2. Scientists will probably be surprised if BA.2 causes new major waves in places where there has only been BA.1On the other hand, a few countries like Japan, which have so far managed to prevent the spread of coronavirus in general, may find it more difficult to suppress BA.2 than BA.1, so they may experience epidemic waves due to BA.2.
Does all this mean that BA.2 is less dangerous than BA.1?
Practically speaking, this is probably true. The factors that determine the threat level of a virus include its inherent pathogenicity (how severe disease it causes), how many people it infects (its infectivity), and how much immune protection people have against it. As far as we know, BA.2 is unlikely to cause more severe disease than BA.1, but may be up to 50% more contagious. Increased infectivity may gradually translate into more hospitalisations and deaths as more people become infected, even if most do not become seriously ill. On the other hand, however, already in many countries a large proportion of the population has good immunity from both vaccines and previous infections (natural immunity), which is likely to significantly reduce both the number and severity of BA.2 infections.
Is BA.2 a stealth variant that goes under the radar?
Some have claimed that BA.2. is undetectable by tests, but the truth is that it is caught by both molecular PCR and rapid tests, as is the case with other variants of the coronavirus.
Source: Proto Thema
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