Hayadan > Everything you wanted to know about the delta breed, but didn't feel comfortable asking

Everything you wanted to know about the delta breed, but didn't feel comfortable asking

Patients with the delta strain produce a thousand times more viruses than patients with previous strains of the corona, this is one of the most contagious viruses. There are many open questions about it, including what is the mortality rate from it, and what is the strategy required to defeat it

The delta strain spreads rapidly. Illustration: depositphotos.com

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Something strange is happening with the delta strain of the corona virus. The delta strain attacked a country with more than a billion Indians a few months ago and brought it to its knees - but we are still not sure what exactly its features are.

It spreads in the world at lightning speed - faster than any other species - and conquers cities and continents, but the vaccines stop it. or not. Or yes. Every day provides different answers from a different official in the world, not to mention my last taxi driver, who knows exactly how to save the day and is really frustrated that no one listens to him, except the passengers.

In this entry I will try to clarify what we know today about the delta strain (and what not), why the government is so afraid of the situation, why a closure can help (and may not) and the real dangers that this new strain brings with it.

Delta strain - this is your life

Let's start with a little history. The delta strain was first discovered in India in December 2020. It is no exaggeration to say that it caused a humanitarian disaster there in the big cities, where people begged for donations of oxygen that could keep their loved ones alive[1]. According to the estimates of health experts, the virus killed between three and five million Indians in a period of a few months[2]. Preliminary studies show that approximately two-thirds of the country's residents have been infected with the virus and have developed antibodies against it[3]. Will these antibodies help them if the virus returns in a year, or if it undergoes another significant mutation? No one is sure of that anymore.

The world was convinced of one thing thanks to the Indian tragedy: it is impossible to let such a virus spread just like that among the population, or the health systems will simply collapse. It is necessary to vaccinate as many people as possible, emphasize the use of various safety measures such as masks and, in the worst case, closures, and prepare the hospitals for a blow that may come at breakneck speed, from the moment the virus gains momentum in the population.

And it is gaining momentum. Oh, how he's picking up speed.

The delta strain has already managed to reach 130 countries in the world. In 55 of them it became the most common type, and in all the rest it is progressing safely. In the United States, 93 percent of all newly confirmed cases were infected with the delta strain[4]. Australia went into a panic due to the intrusion of the delta strain and imposed a lockdown on millions of citizens[5]. Asian countries that thought they got rid of the corona virus - Japan, South Korea, Malaysia, Thailand - are experiencing new outbreaks[6]. In China, where there were mass pool parties throughout the last year, they started to return to the policy of hermetic closures[7].

But why is everyone so scared?

Is the delta strain more deadly?

There is still no unequivocal evidence that would allow us to answer this question with confidence. But there are clues. In a study from Canada, the consequences of infection with the delta strain were examined, and it was discovered that it results in more than twice (120%) hospitalizations, an almost fourfold increase in the chance of going to the emergency room, and a more than twofold increase in the chance of death[8]. A parallel study from Singapore revealed similar results, according to which those infected with the delta strain are at a higher risk of going to the emergency room, needing oxygen, and dying[9]. A study from Scotland determined that the chance of hospitalization is almost twice as great as that posed by the alpha strain of the virus[10], which we enjoyed in the last closure.

bothersome? Definitely. But unless the delta strain turns out to be an order of magnitude more deadly than the other strains, we should probably worry about another reason: the delta strain is much more contagious. And this, contrary to what intuition would tell us, is a bigger problem than the supposed increase in the lethality of the virus.

The delta strain: more contagious, more dangerous

The delta strain has at least three characteristics that distinguish it from the original virus.

First, it creates more copies of itself. According to a study from China, patients with the delta strain produce a thousand times more virions (one per virus) than those infected with the original virus. Not surprisingly, they are also more contagious, as they release much larger amounts of viruses into the air[11].

Second, the delta strain begins to spread faster than the other strains: only about four days from the moment of infection, as opposed to the six days we have learned to expect.

Third and last (for now), the carriers continue to be contagious for a longer time: a full 18 days, instead of just 13 days.

All these together result in the fact that "the war has changed", as the CDC researchers defined at the end of July, in an internal briefing document. They bring in the document the same evidence that I described regarding the severity of the disease that the virus causes, but place the emphasis on its enhanced ability to infect. According to the document, the delta strain is twice as contagious as the original virus. In the words of the researchers, it is more contagious than the SARS virus from the early 1918s, Ebola, the common cold, the seasonal flu, the Spanish flu of XNUMX and the smallpox. He leaves all these far behind. Only highly contagious viruses - such as chicken pox - reach the same level of infectivity as the delta strain[12].

As the director of the CDC, Dr. Rochelle Walansky, said -

"I think people need to understand that we don't shout "wolf, wolf!" Here. This is serious. It is one of the most contagious viruses we know. Measles, chicken pox, this virus - they are all on the same level. When you think about epidemics with an R0 of eight or nine - there aren't many of those."[13]

Let's recall for a moment what the R0 means. This is a measure that describes the average number of people that one patient infects. According to the CDC, the R0 of the delta strain is between 5 and 8.5. That is, each person infected with the virus is expected to infect eight people and one dwarf, on average.

The significance of this contagiousness is enormous. In fact, it is she who makes the virus so dangerous for society as a whole. Why?

As usual, the math is to blame for everything.

To illustrate the point, let's do a quick comparison between two hypothetical viruses.

The first virus was called "slow and deadly". It has an R0 of 2, which means that each patient transmits it to two other patients. This species is also very deadly, with a mortality rate of ten percent.

The second virus is called "fast and furious". It boasts an R0 of 5, but its ability to inflict damage is very limited: the mortality rate among patients is only 0.1 percent.

Let's assume for a moment that it takes a virus one day to spread in each jump. On the first day, the two viruses race, each with only one patient.

On the second day, "Slow and Deadly" infects two people. On the third day, four people. On the fourth day, eight people, and so on and so forth. After two weeks, it had infected approximately 16,384 people. If we assume that ten percent of them will die, then the total number of deaths caused by the virus in two weeks is 1,638. It's quite a lot, but let's examine the second competitor in the race and see how he fares.

The "fast and furious" virus infected five people on the second day. On the third day - 25 people. On the fourth day, the number had already jumped to 125. Let's jump ahead two weeks, and we will find that "Fast and Furious" has already infected about six billion people. Or in other words - almost all the inhabitants of the earth. Even if this 'weak' strain only kills a tenth of a percent of them, it's still six million dead, plus or minus.

These are exaggerated numbers, of course, and the virus does not spread in jumps of one day, but in intervals of a week or two at a time. But the meaning is clear: viruses that are more contagious and less lethal can be much more harmful in the overall view of things. They can spread quickly, infect a large number of people - some of whom will be elderly and people with underlying diseases and with an immune system that does not function well - and reach the whole society before they disappear due to the immunity that many develop against them. This is, apparently, what happened in India, and that is why the hospitals there were unable to cope with the enormous load created in a few weeks. This is also the reason why the delta variety has become the most common in the world, and many countries have to deal with it these days.

By the way, one big disadvantage that "Fast and Furious" has is that following the passage of the virus among the population, almost everyone is vaccinated against it. And again, this is probably what happened in India. But as I already wrote, there is no certainty that the immunity remains for a long time, or that the next version of the virus will not be able to bypass this immunity. And in any case, by the time you reach that herd immunity (or close to it), the country has already experienced a major health disaster that affects the entire health system.

And this is the real danger of the delta strain, in countries where citizens are not vaccinated in large numbers.

But how does the virus really deal with the vaccines?

Does the vaccine protect against the delta strain?

It is important to note that in this section I refer only to the Pfizer vaccine, which most people in Israel received.

Let's start with the positive side: yes. The vaccine unequivocally protects against the delta strain. Vaccinated people gain powerful protection against the virus.

This is a bombastic statement - but true. Still, it is important to pay attention to the small details as well.

Let's start with the fact that the vaccine does not completely prevent the infection of the vaccinated. The delta strain produces, as mentioned, a huge number of virions that spread into the environment, and these can burden even vaccinated people who received the double vaccine. The vaccine still helps in reducing the damage caused by the disease: if you have been vaccinated twice, your chances of being admitted to the hospital drop by about ninety percent.

And now for the bad news. The vaccine does help neutralize the damage of the disease, but its ability to prevent infection is more limited. Specifically, the initial studies speak of a success of between sixty and ninety percent in preventing the development of the disease in the vaccinated.

It is important to say that this phenomenon, in which a vaccine does not protect the vaccinated one hundred percent, is well known to medical science. These infections are called Breakthrough infections, for an obvious reason: the virus breaks through the immune system despite the help it received, and succeeds in multiplying in the host's body cells.

Infections of this type are not common, as mentioned, but they certainly occur. The worse news is that, at least in some cases, vaccinated people who develop the disease produce the same amount of virus as unvaccinated patients. That is, in extreme situations you can be vaccinated, look healthy, walk complacently on the train without a mask - and still spread the delta strain viruses around you.

This, by the way, is why the CDC recently recommended that the vaccinated continue to wear masks in closed spaces. And this is also the reason why I get angry every time I travel by train and see people sitting without masks, and assume that because they are vaccinated - they cannot transmit the virus to others, or contract it themselves.

So do you need a closure?

And now to the question of the questions: Is a closure necessary to deal with the delta strain?

On the one hand, we know from the previous waves in the world that closures are unequivocally successful in slowing down the spread of the virus. And there is no doubt that there is an urgent need to slow its spread in Israel. At the beginning of the week, we were informed that the number of verified people had reached 5,000 per day[14], and if the situation does not change sharply, then in ten days we will already reach 10,000 verified a day, and the numbers will only continue to rise.

On the other hand, you also have to recognize the reality, and the fact is that the citizens of Israel are tired of prisons. The third lockdown was kind of one big hoax: few took it seriously, and as a result (and aided by the particularly contagious British strain) it did not result in the same slowdown in morbidity that we saw in the first and second lockdowns. So will the public really agree to respect a fourth closure? It's hard to know in advance, but I suspect that unless such a closure is strictly and strictly enforced, it won't do much in stopping the spread of the delta strain.

Another possible point against the blockade is, quite simply, Britain. In mid-July 2021, the state decided to lift most of the restrictions - including wearing masks in closed spaces and maintaining social distance. There was no worse time to do it, apparently, but then the unbelievable happened: the numbers of patients began to drop. By early August, the numbers of confirmed patients had dropped to half of what they were in mid-August[15].

The accepted opinion is that this is not a herd immunity effect, because the UK - like Israel - has not been able to vaccinate enough potential patients to reach this level[16]. One of the main guesses at the moment is that the decrease in the number of patients was caused by the closing of schools and going on summer vacation[17]. If this is really the reason, then one can learn from the fact that the spread of the virus among the population is getting a new effect thanks to the school children. And if we in Israel are experiencing the current dramatic increase in the number of patients even when the schools are closed, then opening them in a month could make the progress much worse.

Still, can Israel rely on the results of the three-week British experiment, remove all restrictions and expect a similar decrease in the number of patients? In my opinion (and probably also for the taste of the ministers in the country), this would be a very big bet, based only on the results from Britain. One cannot so easily forget the events in India, where the restrictions were zero. It is also impossible to ignore what is happening in Iran these very days: hospitals are collapsing that are forced to treat patients outside the buildings, and 500 die a day[18]. All this courtesy of Delta Zen[19].

So no - I would not recommend removing the restrictions in Israel before we know better how this virus works. Nor would I rule out the possibility of imposing a blockade just because "in Britain they didn't impose it and it worked for them". We are not Britain, and even the British don't understand where they got this luck from. And on the other hand, we must not proceed with the closure without carefully considering the consequences for the economy and public sentiment. As was already clear from the end of 2020, we have to learn to live with the virus and weigh the risks against the gains. I don't envy ministers who have to decide whether to impose a lockdown in the coming weeks.

The war has changed

אז מה עושים?

First and foremost: treat this strain with the seriousness it deserves. As the CDC said - "the war has changed". The delta strain spreads at breakneck speed, and exposure of a few seconds to an infected person without a mask is enough for you to become infected. Yes, to that extent[20]. And as I already wrote, the vaccine does not provide perfect protection. Don't be complacent.

Second, obey the instructions. Contrary to all the conspiracies, there are people up there in the Ministry of Health who care about us. And the cynics will add that if not for us, then at least for their job which will suffer badly if they make the wrong decisions. If the order of the hour is to put on a mask - you put on a mask and don't get smart. If there is a green, purple or orange-with-yellowish-dots note - you don't try to get around it in all kinds of crooked ways. Ultimately, we all want to avoid more severe restrictions or a lockout. If we cheat, we only cheat ourselves. And as unpleasant as it is - you can also admonish those who do not obey the instructions. In the end, it contributes to the morbidity of all of us.

Third, get vaccinated. I guess I am not repeating much here about the words of Prime Minister Bennett, the Minister of Health and others, but I will repeat them anyway. If you are of the right age to get vaccinated for the first or second time - do it. If you are allowed to get vaccinated for the third time - go for it too. Vaccinations are our best way to stop the spread of this particular strain. They are not perfect - no vaccine is perfect - but they give you a shield thanks to which you can avoid the most harmful effects of the virus. Oh, and also help the rest of society, because the chances of you infecting others are significantly less. So why not take advantage of this protection?

And last but not least, and this is already a recommendation to the government: close the damn borders already. Half a year ago I wrote an entire record here about what needs to be done following the third wave, and the main emphasis in it was on closing the borders to prevent the next dangerous strain of the virus from entering Israel. Not closing borders at the level of a total curfew of exits or entries, but in terms of strict adherence to real isolation of at least two weeks, with high fines and even imprisonment of those who violate the guidelines.

Did they do it? don't make me laugh Those in charge said the right words, and that too with difficulty.

Again and again we make the same mistake: we assume that we don't need to fear the virus anymore, and we throw all the safety measures in the trash. If we reach a shutdown, then the responsibility for this is entirely on the shoulders of the senior officials in the government (previous or current) who chose to ignore the ability of the virus to undergo evolution, and the recommendations of senior officials in the health system not to be complacent.

If we were careful about proper screening when entering Israel, and given the high percentage of vaccinated people that we enjoy, then it is quite possible that we would have succeeded in completely preventing the delta variety from making aliyah.

We assumed that the trouble was over, that there was nothing more to fear, and we are paying for it now. The delta strain is here, it's dangerous, and it's time we learn from our mistakes and stop repeating them.

Only health, for all of us.

[1] https://www.aljazeera.com/gallery/2021/4/26/oxygen-demand-outstrips-supply-in-indias-covid-hotspots

[2] https://www.npr.org/2021/07/21/1018686321/study-suggests-that-indias-pandemic-death-toll-is-higher-than-official-data

[3] https://www.reuters.com/world/india/india-govt-survey-shows-two-thirds-have-coronavirus-antibodies-2021-07-20/

[4] https://thehill.com/policy/healthcare/566284-cdc-delta-variant-accounts-for-93-percent-of-all-infections

[5] https://edition.cnn.com/2021/08/05/australia/sydney-covid-deaths-lockdown-intl-hnk/index.html

[6] https://edition.cnn.com/2021/08/04/asia/southeast-asia-delta-covid-explainer-intl-hnk/index.html

[7] https://apnews.com/article/China-delta-variant-coronavirus-pandemic-lockdown-292b84b26eb41888c579a6460c2647c3

[8] https://www.medrxiv.org/content/10.1101/2021.07.05.21260050v2.full.pdf

[9] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3861566

[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8201647/

[11] https://www.medrxiv.org/content/10.1101/2021.07.07.21260122v2