Episode #75 -  Omicron sub variant risk

19 July 2022 | Science conversation

Vismita Gupta-Smith

What do we know so far about the sub variants of Omicron? Are they more severe? Are they more transmissible? And how is risk being perceived by the experts and the public?

Hello and welcome to Science in 5 I am Vismita Gupta-Smith.

We are talking to Dr Maria Van Kerkhove today. Welcome, Maria. Let's start with the sub variants of Omicron that we are seeing so far. What do we know about them?

Dr Maria Van Kerkhove

So hi Vismita. There are many sub variants of Omicron, all classified as Omicron and variants of concern that WHO is tracking actually many of them. 

The ones that we are focusing on right now are particularly BA.4, BA.5 and BA.2.75.

Now there are several other sub lineages that we are tracking at a global level. But I want to reiterate that all of the sub lineages of Omicron are classified as variants of concern.

Each one of these variants, each iteration of SARS-CoV-2, are of concern for WHO because this virus is circulating at such an intense level globally.

Vismita Gupta-Smith

Maria, what do we know about the transmissibility and the severity of these sub variants?

Dr Maria Van Kerkhove

So with regards to the sub lineages of Omicron with BA.4 and BA.5, these are the most transmissible variants that we have seen yet.

In fact, BA.5 has a growth advantage over the other sub lineages that have been detected.

With regards to severity, we have not seen an increase in severity of people infected with BA.5 compared to the other sub lineages BA.1, BA.2 for example. 

But this is based on our ability to assess this at a global level. It's based on data that is shared with WHO, that's collected by surveillance officers, medical professionals, people around the world. And that data is becoming more and more limited.

I just want to mention BA.2.75. At the present time, we have very few sequences of this particular sub lineage that are available publicly, but we are concerned about this sub lineage as well.

Vismita Gupta-Smith

Maria, what are the trends we are seeing with these sub variants?

Dr Maria Van Kerkhove

So we are seeing an increase in case detections around the world.

In fact, more than 5.7 million cases were reported to WHO last week and those are the cases that we know about. And that is an underestimate, because surveillance activities have declined drastically around the world, including testing.

Although self testing is increasing in many countries, that's not captured by surveillance systems.

We do see an increase in the proportion of cases that are BA.5 that has grown over the last four weeks and we expect that trend to continue. So some countries are starting to see an increase, another wave of activity of SARS-CoV-2.

We are also tracking very closely the amount of people who are infected that require hospitalization, that need to be admitted to an intensive care unit, need oxygen and people who are dying.

We are concerned about the high level of deaths that we have seen in a number of weeks.

Deaths are averaging around… are reported around 10,000 per week and that's really far too high. When we have tools that can actually prevent the deaths.

Vismita Gupta-Smith

Maria, let's talk about risk and it's perception now.

The emergency committee has noted that the way the risk is being perceived by the public is different from the way experts perceive it. Speak to us about that.

Dr Maria Van Kerkhove

So the virus itself, as we talked about, continues to evolve. And there's an uncertainty about how this virus will change over time. We have some clues about this, but we don't know for certain. 

So the risk remains high because this virus is still killing people at a high level.

In terms of public perception, we do find that people really want to move on from this pandemic, but the risk is still very much there. And a lot of this is driven by a lack of access to vaccines around the world. 

You have to remember that there are hundreds of millions, if not billions of people, who have not received a full course of vaccine yet.

2.5 years into this pandemic, and they are at increased risk of severe disease and dying. But we also have to reduce the spread. So you may be not in an at risk population, but your loved ones maybe.

So what you do to keep yourself safe also has an impact on others. Perhaps you live with someone who's vulnerable. 

So do everything that you can. Masks, distancing, ventilation, get vaccinated, spend more time outdoors than indoors. Work from home when you're unwell. It's not just about you. It's about governments providing support to you to carry out these lifesaving actions.

So we're very much still in this pandemic. We need to continue to be vigilant, need to be cautious, live our lives, live our lives responsibly and safely.

Vismita Gupta-Smith

Thank you, Maria. That was Science in 5 today.

Until next time then, stay safe, stay healthy and stick with science.