Coronavirus: What Is The Impact Of The BA.5 Variant?

The SARS CoV 2 (coronavirus) is not done with mankind yet. Each time the virus mutates, it starts another cycle of travel around the world, causing repeated waves of infections (and concern) in impacted countries before the situation once again starts improving.

The current BA.5 wave tearing through several countries around the globe is part of one such cycle. With a major difference – the BA.5 subvariant can spread more easily and bind to human cells more strongly than earlier variants. Even in those who are fully vaccinated. First discovered in South Africa in February this year, BA.5 is a subvariant of Omicron. The speed of spread seen there caused a wave of infections bigger than previous Omicron subvariants. BA.5 soon spread to other countries to become the dominant variant in each of those countries. Especially affected were the European countries and later the United States, although the reach of BA.5 has now increased beyond these geographies. In fact, in the US alone, BA.5 grew from 10% of all cases in June to 80% of all reported cases by late July. 

It is the mutations in Omicron and especially in the BA.5 subvariant that confer upon it, the ability to transmit more easily. When first discovered in November 2021, Omicron had over 43 mutations, including more than 20 mutations in the spike protein (against which vaccines act). However, BA.5 has three additional mutations that help it to remain disguised and bypass recognition by antibodies, even if the immune system has been fortified by vaccination and earlier infections. This is what we refer to as “immune escape”. 

In addition, vaccine-induced antibodies are waning especially in those who have not yet availed of a booster dose, and hence, protection is fading. Infection–induced antibodies from previous infections with Delta or even older Omicron subvariants are no longer providing sustained protection and re-infection is increasingly being seen. Compounding the situation is the resumption of international travel and relaxation of mask mandates. That said, vaccines have not been rendered ineffective. They continue to provide robust protection against severe disease, hospitalization, and fatal outcomes.

Almost as a silver-lining (if one could call it that), the symptoms of COVID-19 induced by BA.5 are largely mild, especially in vaccinated individuals. The most common symptoms seen with BA.5 include extreme fatigue, runny nose, sore throat, headache, body ache, and persistent cough (lasting for 5 to 6 days). Loss of taste and smell has conspicuously been absent. Fortunately, most symptoms respond to and improve with outpatient care. The time taken by a person with BA.5 to test negative has lengthened to about 10 days. Hence, after 7-day isolation, complying with the further 7-day masking recommendation is strongly recommended.

Hospitalizations can and do still occur, especially in vulnerable groups – the elderly, those with co-morbidities, those on immunosuppression, etc. It is important to remember that with easy-to-administer home testing becoming readily available and results largely going unreported, the actual numbers may be several times higher than those declared. The mode of spread of BA.5 remains the same – respiratory spread is most common. Aerosols are generated when an infected person speaks, sneezes, or coughs, stays in the air for some time, and can cause the infection to spread to those around. 

Thankfully, the spread can be minimized if individuals continue to practice COVID-appropriate behaviour – wearing a multi-layer mask, maintaining distancing, frequent handwashing, and availing of primary vaccination, as well as a booster, are all essential and form the backbone of our defense. Most importantly, remaining aware of the evolving COVID-19 situation through information from credible health sources is critical.

(Dr. Vikram Vora, Medical Director, India Subcontinent, International SOS)

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