5 Burning Questions: Are Omicron BA.4, BA.5 the Most Contagious Subvariants?



The two newest Omicron subvariants BA.4 & BA.5 are spreading rapidly across continents. What do we know about the new iterations so far? How are they different and what cautions should we take?

What are Omicron BA.4 & BA.5?

BA.4 & BA.5 were first identified in South Africa and are becoming the dominant strains in Europe and the U.S.. According to WHO, these new subvariants have been spreading in more than 40 countries and hence been added to its monitoring list.

What are the symptoms of an infection with BA.4 & BA.5?

These subvariants do not have markedly divergent symptoms form earlier versions of Omicron. Some of the common symptoms include persistent cough, sore throat, runny nose and sneezing, while some may experience fatigue, headache and fever.

Are BA.4 & BA.5 more contagious? Do they cause more severe disease?

They do appear to be spreading more easily as they are able to bypass immunity from a past infection or vaccination. Fortunately, they are not thought to be any more lethal than other strains of viruses.

For example, there is a drop in hospitalizations and deaths during the BA.4 & BA.5 wave than previous waves in South Africa; while there are no such drops in Portugal despite its relatively higher vaccination rate. It is probable that a denser or aging population is prone to severe infections, and the high infection rate of previous variants allowed most South African to develop hybrid immunity that offers strong protection against severe disease.

Can BA.4 & BA.5 still infect recovered patients or vaccinated persons?

Although it is unclear if the two new subvariants are causing more severe disease, studies have found out that they can bypass antibodies created by past vaccination or prior infection, meaning people can be reinfected even if they had Omicron or vaccinated earlier this year. Some findings even suggest that antibodies triggered by vaccination are at least 4 times more effective at blocking their predecessors than at BA.4 & BA.5

How do we protect ourselves against BA.4 & BA.5?

Given their highly contagious nature, it is important to maintain good hygiene at all times and wear face masks. The best things we could do are to receive booster shots to enhance our antibodies level, and get rapid tests after attending gatherings, large-scale events and experiencing symptoms. Besides, since most people infected by BA.4 & BA.5 are asymptomatic, people at high risks such as the elderly, children, patients with chronic illness and unvaccinated persons should get tested regularly to protect yourself and your family.

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