The virus does not have a "characteristic disease", and it is embarrassing to see people
The strains of various XBBs account for an increasing proportion of virus strains circulating in China, and there are more and more legends of Eryang on the Internet. Previously, when XBB.1.5 came out, it was rumored online that this strain of the virus caused diarrhea. According to CDC data, XBB.1.5 and its subclades account for nearly 30% of all XBB strains detected in China [1].
In the week of 4/21-4/27 alone, 230 of the 2096 cases of national viral genome sequencing were in the XBB.1.5 branch. At this rate, 10% of people infected with the new crown today have XBB.1.5. But when the whole country did not detect XBB.1.5, the antidiarrheal montmorillonite was snatched out of stock, and when XBB.1.5 really took root in China, not only did no one complain about the long squatting time, but said that it was national strep throat. Could it be that the montmorillonite bought before now comes in handy to prevent the crisis of insufficient pits?
Like XBB.1.5 and diarrhea, it is not uncommon for a certain strain of the new coronavirus to have some characteristic symptoms. XBB.1.16 Legend has it that it attacks the eye specifically, causing conjunctivitis. The new virus strain, if it does not come with a special technique that specifically causes XXX, is not very embarrassed to greet everyone.
But a very interesting phenomenon, "a virus strain specifically causes XX symptoms", such statements are often the most vigorous spread by some websites that often spread rumors, or some non-medical, scientific majors are forwarding. Authoritative scientific institutions and reliable popular science bloggers almost never say what symptoms a certain new coronavirus strain specifically causes.
This phenomenon actually implies from the side that the statement that different new coronavirus strains have "characteristic diseases" or "special symptoms" is not reliable.
"Characteristic disease" satisfies the desire for certainty
Lately I've been wondering why phrases like "a strain of the virus causes a symptom" are so marketable. There may be two reasons, one is that in the face of illness, we want certainty in our hearts. Especially a tiny virus like the new crown, which cannot be seen or touched, on the one hand, makes us feel that this disease is more "mysterious", on the other hand, it also makes us more expectant that someone will tell us what the disease is, and the more certain the better.
Professional medical information will say that most people's symptoms after contracting the new crown will be similar to common respiratory infections, common fever, sore throat and so on. From a scientific point of view, these symptom information has been very clear, but compared with the certainty that ordinary people want, I am afraid that there is a long way off. What many people want to know is not how likely they will have a fever after being infected with the new crown, but the fever in the first few days to the first few days after infection. It is better to tell me that if I am infected, the fever starts in the first few hours, how many hours will the fever subside, and if it is 25 hours, then you can't tell me about a day, because a day is 24 hours. And also be able to say clearly, the fever will reach a few degrees, 40 degrees is 40 degrees, can not be said to be more than 39 degrees.
The standard of certainty that ordinary people want is too high, and professional medical information cannot be satisfied. But "a strain of the virus causes a certain symptom" can satisfy the certainty that everyone wants. XBB.1.5 causes diarrhea, XBB.1.16 specifically causes conjunctivitis, are very clear to tell you what will happen if you get it, just to meet everyone's lack of certainty in the face of invisible and intangible viruses. When rumors tell you that contracting the current virus will cause diarrhea, it is one thing to feel uncomfortable in the stomach, but at least the heart is steady.
At this level, rumors such as the new crown is small AIDS are similar. Although the person who said this is estimated to have limited understanding of what AIDS is, once there is a characterization of small AIDS, this is a definitive terminal illness, a definite bad one, and a certainty.
But this certainty, like those characteristic diseases, is false. The new crown virus infects cells with ACE2 receptors through the spike protein, and as an RNA virus that is not a retrovirus, the new crown cannot be integrated into the genome of infected cells. The culprit of AIDS, HIV infection, is an immune cell, CD4 T cells, which can also be integrated into the cell's genome as a retrovirus, becoming a lifelong virus. A completely different pathogenic mechanism has led to an acute infection (new crown) and a chronic infection (HIV), but explaining these, involving certain academic concepts, is far less penetrating than the three words "little AIDS".
What's more, in the specific symptoms of the new crown, science really cannot achieve some of the certainty that the people expect. Not to mention that it is difficult to have a consistent viral infection, even if the dose and composition of vaccination are very clear, common adverse reactions such as fever are very different from individual to individual. For example, in the phase III clinical trial of the Pfizer/BioNTech new crown mRNA vaccine, the proportion of common adverse reactions such as fever and fatigue after the first and second injections in the group over 55 years old [2]:
After the first dose of the vaccine, 34 percent reported fatigue and 51 percent for the second dose. This is very common, but two-thirds after the first injection, half of the people did not feel tired after the second injection, and about one-fifth of the placebo felt fatigued. Why does vaccination cause fatigue, a common adverse reaction? Many are adjuncts to the immune response. Some symptoms of new crown infection, such as fever, also have the shadow of the immune system responding to the virus and producing an immune response. But even with the same vaccine, the same dose, everyone's response can be so different, let alone the virus infection with greater individual differences?
Why don't rigorous scientific institutions tell you which day to day of fever after contracting the new crown, because the scientific law determines that there are huge individual differences in the common symptoms of these respiratory viral infections. We can find some patterns, such as many people have fever and how long it usually lasts, just as we can summarize that the proportion of common adverse reactions after the second dose of the vaccine is higher than that of the first dose, but we cannot provide a specific prediction of individual symptoms.
Many people like to record what the symptoms are from day to day after being infected with the new crown, and these sharing are also helpful for people who have just been infected, which can have some reference, so as not to feel that they are alone and sick. However, do not absolutize these personal experiences. And if someone tells you what the symptoms must be after getting sick, then this person is either a liar or an idiot.
"Characteristic diseases" meet the "different" expectations of different virus strains
"A virus strain causes a certain symptom" not only satisfies our desire for certainty of the disease, but also satisfies our obsession that different virus strains should always be different.
When we say that Delta and Omicron are two different strains of the new coronavirus, the attention will naturally focus on the word "different", rather than thinking that these two are actually new coronaviruses. So we also think about what is different. To say that Omicron is more transmissible and has significant immune escape is more scientific, but abstract to the public. But once you say that you sneeze downstairs, upstairs is infected, and whether you are vaccinated or not, this is very graphic, and it is in line with the "different feeling" in everyone's mind - although it is not so scientifically accurate.
Now the succession of the new coronavirus strain is carried out inside Omicron, BQ.1 replaces BA.5, XBB replaces BQ.1, and even XBB.1.16 and XBB.1.5 come out on the front and back feet. At this time, without making up the difference in symptoms, how can we convince ourselves that these virus strains are different?
When we hear that BF.7 swallowing blades, XBB.1.5 diarrhea, XBB.1.16 conjunctivitis, these various symptoms not only frighten us, but also satisfy the doubt of "what is different about these guys".
However, the reverie that different new coronavirus strains have characteristic diseases is easily punctured scientifically. For example, XBB.1.5 and XBB.1.16, the two virus strains are very similar in genome, with only two amino acid differences in the S protein:
Even if we assume that because there are ACE2 receptors in the eyes and intestines, the new crown can bind to the ACE2 receptors in these places through the S protein to attack these parts, but two virus strains with such a similar S protein, one specifically attacks the eye and the other specifically attacks the intestine?
In the first wave of epidemics encountered in China, BF.7 and BA.5.2 were actually very similar, BF.7 is BA.5.2.1.7, the "grandson" of BA.5.2, the two have only one amino acid mutation in the S protein. Can the so-called northern BF.7 swallow blade be formed, and the southern BA.5.2 is milder?
The spectrum of symptoms of the new crown is not so variable
In fact, even when the original strain, alpha, delta, and Omicron BA.1/2, which are genomically different virus strains, are compared together, the symptom lineage is very similar.
For example, in England, a study of new crown symptoms based on 1.5 million people covered the period from the original strain to BA.2, and the proportion of infected people reported symptoms during the epidemic of different virus strains was different, such as cough was 8.8% at the original strain and 35.1% at BA.2 [3]. The difference in proportion is not small, but this symptom is present in both virus strains and is not uncommon. During the period when both strains of the virus are circulating, it is normal for infected people to have this symptom, but it is also normal for infected people to have this symptom.
One of the earliest mythical symptoms of the new crown is the failure of smell and taste, which was once regarded as a special symptom that distinguishes the new crown virus from other respiratory infections. But in fact, there are many people who have a bad sense of smell and taste when they have a cold or flu. In the early days of the epidemic, when interviewing Fauci, a reporter asked many people what happened to the legendary sense of smell and taste, and Fauci was surprised at the time, saying that this is also found in other respiratory infectious diseases. Nowadays, including the CDC, it is pointed out that smell and taste failure is a similar symptom of the new crown and influenza, but the proportion of new crown may be higher [4].
In the English study, the proportion of smell and taste failure was 11.9% at the time of the original plant, 14.5% in alpha, 22.8% in Delta, 9.1% in BA.1 and 11.5% in BA.2. It is true to say that the incidence of olfactory and taste failure has decreased significantly during the Omicron period, but from the absolute incidence rate, it is not uncommon to have olfactory taste failure infected with any virus strain.
If you refer to the definition of common and rare side effects of drugs, the incidence of more than 10% is very common, 1%-10% is common, uncommon is 1 in 1,000 to 1 percent, and rare is in 1 in 10,000 to 1 in 1,000.
Diarrhea that scared many people to buy montmorillonite before, the incidence of the above English study from the original strain to BA.2 is between 6-8%, which has always been "common", but it has never become a virus strain specializing in diarrhea. As for the sore throat that was successfully searched after May Day, the study reported that the number of infected people with sore throats ranged from 13.8 to 48.7%, which has long been among the most common symptoms - in fact, these symptoms are also common in other respiratory infections, such as the A flow, which has not completely disappeared today.
And conjunctivitis that scares many people to study whether to stock up on eye drops, viral conjunctivitis itself is the most common type of conjunctivitis. Although the proportion of eye symptoms caused by the new crown is not alarming, previous studies have shown that the incidence of conjunctivitis is also between 1% and 6% [5].
In general, viral conjunctivitis is more common in children, and a previous Canadian analysis based on the emergency case of the new crown in children also had a proportion of conjunctivitis, with the original strain being 7.6%, alpha 3%, Delta 10%, and Omicron (BA.1/2) 3.9% [6]. Not very common, but it can be counted as a common symptom – at least not rarely.
You know, the difference between BA.1/2 and the original strain can be much greater than the difference between XBB.1.16 and XBB.1.5 or between XBB and BA.1/2, how can XBB.1.16 suddenly become a specialty conjunctivitis?
Take a rational look at the symptoms of the new crown
With any disease, the most immediate feeling for the person concerned is the symptoms. Therefore, we will naturally struggle with the specific symptoms after the new crown infection, whether it will be fever, or diarrhea, how severe it is, and so on.
However, first, the common symptoms of the new crown and other respiratory infectious diseases have a great intersection, we cannot say that the new crown must have a certain symptom, nor can we say that a symptom is the new crown. The various virus strains of the new crown do not have the so-called special symptoms.
Second, there are huge individual differences in the symptoms of infected people. No matter how common the symptoms, many people simply cannot encounter them, and even relatively rare symptoms, when the infection base is huge, many people will encounter them.
A list of common symptoms, such as fever, fatigue, chills, diarrhea, changes in smell and taste, etc., and even conjunctivitis if you prefer, can be used as a reference. However, this reference is not according to the diagram, and does not mean that there will inevitably be these symptoms after infection.
Finally, and most importantly, these common symptoms are slow to recover, not to say which symptoms are life-threatening severe diseases. The coronavirus will not go away, it will always exist, and it will be difficult for us to remain infected forever. Therefore, it is more necessary to learn to rationally view the common symptoms that may or may not be encountered after infection after reducing the risk of severe disease through vaccination and other means.
Personal views do not represent any organization or unit
Resources
1.https://www.chinacdc.cn/jkzt/crb/zl/szkb_11803/
2.https://www.nejm.org/doi/full/10.1056/nejmoa2034577
3.https://www.nature.com/articles/s41467-022-34244-2
4.https://www.cdc.gov/flu/symptoms/flu-vs-covid19.htm
5.https://www.ncbi.nlm.nih.gov/books/NBK470271/
6.https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2802161