Covid-19: What you need to know today

4 months ago 31
google news

I don’t know whether you received that WhatsApp forward about the time traveller who lands up in 2020.

“Which year is this?” she asks someone.

“2020.”

“Ah, the first year of the quarantine.”

If time travel were really possible — like pandemics, they are a recurring theme in dystopian fiction; some even successfully combine both — and if a traveller from the future were to arrive in 2020, it may help us answer questions about the coronavirus disease that we are still wrestling with.

They could be really basic: like, do we find a cure? Or, how long does this last?

Or, they could be morbid: like, how many people die?

Or, they could be scientific. For instance, does being infected give one immunity? And if so, for how long?

It turns out, according to a study published on Thursday in the journal Nature Medicine, that asymptomatic people may produce antibodies that can fight the viral disease for just a few months. The study is based on a small group, but its finding is worrying because it suggests that unlike a few other diseases, where being infected once gives a person lifelong immunity (chicken pox is an example), contracting the coronavirus disease once doesn’t mean a person will not contract it again. To be sure, it also does not mean that they will contract it again — even a trace presence of antibodies may be enough to fight off the disease, and the immune systems of these asymptomatic people might be better primed to face the Sars-CoV2 virus for the second time.

So what does it mean? In the words of the authors, this might have “implications for immunity strategy and serological surveys”.

Their reference is to the thinking in many countries that widely administered antibody tests can be used to identify who is immune and who isn’t, with the former being allowed to return to work, or travel. Now it emerges — caveat: this study is based on a very small sample — that some asymptomatic infected people might not test for these antibodies (and that they may or may not be immune).

With so-called immunity passports being ruled out — for both ethical reasons and scientific ones — everything on the discovery and availability of a vaccine for the coronavirus disease. There are many promising candidates in various stages of testing and trial, and we could have a vaccine by next year. But it won’t be widely available immediately. The world will need seven billion doses (and if it is similar to flu shots, we may have to take one every year) and not everyone will get it. Issues related to ownership, funding, distribution, and prioritisation will need to be worked out. But according to a recent Bloomberg article, there could be a bigger problem with the first vaccines: they may not prevent the coronavirus disease.

Citing Robin Shattock, a professor at Imperial College London — apart from its models that have informed debates on the spread of the pandemic, the institution is also working on a vaccine — the article said that researchers may settle for vaccines that prevent severe disease instead of looking for the perfect one that offers protection from the infection.

“Is that protection against infection?” Shattock said. “Is it protection against illness? Is it protection against severe disease? It’s quite possible a vaccine that only protects against severe disease would be very useful,” he was quoted as saying by Bloomberg.

So, antibody tests can’t really tell if someone is immune and the first vaccines will only offer protection from severe disease, not infection.

Clearly, this is one difficult virus.

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