Qs people asked me on science and my replies to them- Part 253

Krishna: As soon as omicron was first identified in South Africa, two key questions arose: whether this new variant was more infectious than earlier ones, and whether it caused more or less severe disease.

It’s clear from how rapidly the variant has spread and how quickly cases have increased that it is more infectious. But the question of whether omicron has less harmful effects than previous variants – whether it is less “virulent” – is somewhat more complex.

We have more people now who are vaccinated. Most of the vulnerable people in most parts of the world are vaccinated. That changes the equation.

Early results from South Africa (which are still awaiting review) suggested that patients with omicron were less likely to be admitted to hospital than before. And research found that even when admitted, people were less likely to require oxygen, need mechanical ventilation, be admitted to intensive care or die.

But South Africa has a young population compared to much of the world. A relative lack of older, more vulnerable people catching the virus may have been masking the variant’s capabilities.

However, information accrued over the past month has shown that South Africa’s experience isn’t an anomaly. Data from other parts of the world supports the suggestion that omicron is generally causing less severe disease than previous variants.

Several different factors might explain why this is happening. First up, there’s immunity. It could be that prior immunity – which thanks to previous infections and vaccination programmes is now much more common across many parts of the world than in previous waves – is sufficient to reduce rates of severe disease.

For protection against an initial infection, located in the nose and throat, antibodies against a key part of the coronavirus’s outer structure – its spike protein – appear to play the greatest role. However, these wane overtime. Plus, many of the mutations found on omicron affect the spike protein, and so are likely to impair the antibodies’ ability to bind to the virus, reducing the effectiveness of a vaccine or prior infection at preventing new infections.

But for protection against a more severe infection, which tends to be located in the lungs, other immune responses could be playing a more dominant role, such as killer T cells. These are a type of white blood cell that kills foreign substances as well as the body’s own cells that have been infected with the virus.

And early research, yet to be reviewed by scientists, suggests that omicron has very few mutations to the parts of the virus that T cells target. This implies that immunity built up in the past that’s potentially more effective against severe disease should still largely be intact.

This could be a powerful explanation as to why omicron’s virulence appears lower.

However, if daily omicron infections rise to a very high number, as they have, then hospitalisations will also rise. People are still getting sick in large numbers eventhough not very sick, definitely not as sick as Delta would have made them. Breakthrough infections are occurring frequently with omicron.

Mumbai More than 80% of the Omicron cases detected in the state since December 4 are breakthrough infections- that is among people who are fully vaccinated (1). Preliminary observations highlight its immune escaping nature which should be considered as a point of caution. The new variant does evade immunity developed through vaccination or previous infection.

Little is known about whether the mild disease caused by Omicron is due to the virus’ inherent nature or because of the vaccination. Some studies have shown that a previous Covid-19 infection offered 80% protection against the Delta variant, but it offers only 20% protection against Omicron. It is therefore clear that we will see a rise in cases by January-February. Our health systems should be prepared as given our population, the magnitude of the cases could be high.

Health experts say that data on how the virus will behave in senior citizens and the immunocompromised population is not available, but if the caseload increase, hospitalisations are likely. We should be prepared for a third wave in India and other waves in most parts of the world.

It is better to get prepared then getting caught unprepared and face severe consequences when we have an enemy that is changing its shapes and nature very frequently. That is what wise people do.

Footnotes:

1. Omicron cases in Maha: Over 80% breakthrough infections

Q: What is  interoception?

You are familiar with the five senses - touch, sight, hearing, smell, and taste - but not everyone knows that we have an additional sense called interoception.
This is the sense of our body's internal state. It helps us feel and interpret internal signals that regulate vital functions in our body, like hunger, thirst, body temperature, and heart rate.

Although we don't take much notice of it, it's an extremely important sense as it ensures that every system in the body is working optimally.

It does this by alerting us to when our body may be out of balance – such as making us reach for a drink when we feel thirsty or telling us to take our jumper off when we're feeling too hot.

Interoception is also important for our mental health. This is because it contributes to many psychological processes - including decision making, social ability, and emotional wellbeing.

Disrupted interoception is even reported in many mental health conditions – including depression, anxiety, and eating disorders. It may also explain why many mental health conditions share similar symptoms – such as disturbed sleep or fatigue.

Interoception is contemporarily defined as the sense of the internal state of the body. This can be both conscious and non-conscious. It encompasses the brain's process of integrating signals relayed from the body into specific subregions—like the brainstem, thalamus, insula, somatosensory, and anterior cingulate cortex—allowing for a nuanced representation of the physiological state of the body. This is important for maintaining homeostatic conditions in the body and, potentially, facilitating self-awareness.

Q: Why are scientific papers written in the most boring languages?