How sick will people infected with the new coronavirus Omicron mutant strain be?
Never since the pandemic has the media's understanding of the symptoms of covid-19 patients as it does now.
I'm as anxious as everyone else is to know what the exact answer is. Because life and health are at stake, misinformation can have disastrous consequences.
And there is only one truth.
So today we're going to let the data tell us the truth again.
How serious is the disease of Omicron infected people?
If we are unfortunate enough to be infected with the Omicron mutant strain, how serious the disease will be and what the prognosis is, is our biggest concern.
On 16 December 2021, a South African study published in the British Medical Journal (BMJ) provided evidence on the proportion of hospitalizations for people infected with Omicron.
The results showed that results based on 78,000 positive Omicron tests showed that those infected with Omicron were at a 29% lower risk of hospitalization than those infected with other mutant strains compared to the first wave.
As a result, the researchers believe that the Omicron mutation strain is less diseased than the Delta mutation strain.
However, the study's conclusions were immediately widely questioned because the Omicron strain had a very high immune evasion rate, which included a higher proportion of vaccinators and previously infected people, and this study also showed that the effectiveness of two doses of Pfizer/BioNTech's BNT162b2 mRNA vaccine in preventing hospitalizations in infected people remained 70%.
Therefore, it can only be said that the proportion of hospitalizations of Omicron infected people in the fourth wave of the epidemic is lower than that of the new crown virus infection in the first wave of unvaccinated people. The immune status of the infected populations compared by the researchers has been very different, and the prognosis is naturally different.
Still, the South African study shows that in the current real world, the proportion of hospitalizations for people infected with Omicron is indeed lower than before.
On December 16, 2021, Danish scholars published an epidemiological study of 785 Danish Omicron infected people at Euro Surveill (European Testing)[2], which made a more objective report on the severity of the condition of Omicron infected people in the real world.
Because the study compared Omicron's condition with those infected with the Delta mutant strain infected at the same time, it provided very important information.
Let's start with the severity of Omicron infection: 1.2% hospitalized vs. Delta infected: 1.5%;
Omicron infected: 0.13% into the ICU vs. Delta infected: 0.11%; Omicron infected: no case deaths vs. Delta infected: 0.07%.
As you can see, the symptoms of real-world Omicron infected people reported by Denmark are indeed not severe. But is the disease milder than the Delta mutant strain? There is no statistical comparison in this article, and we suspect that the authors are concerned that the conclusions are unreliable, taking into account the small sample size.
However, numerically only, the severity of the disease of those infected with the Omicron strain and those infected with the Delta strain in this group was not significant; it should be noted that the Omicron group had a higher proportion of those who were fully/intensively vaccinated (83.1% vs. 53.2%) and those with previous infections (4.3% vs. 0.9%) than the Delta group.
And, I don't know if you noticed, in real-world studies in Denmark, only 1.5% of infected people with Delta mutant strains were hospitalized, 0.11% needed to live in an ICU, and the case fatality rate was only 0.07%! That is to say, in the Danish study, not only were the Omicron-infected people less ill, but the Delta-infected people were also less serious.
At present, the new crown is significantly less ill, so does it still need to be vaccinated?
Whether it is South Africa or Denmark, it shows that in the real world, people infected with the new crown virus seem to be less serious.
So many friends are cheering "the new crown infection has become a common cold, such a big Christmas gift!" ”
wait!
Need to see who the infected people are in South Africa and Denmark.
Because the two key influencing factors that affect the severity of the condition after THE new crown virus infection are:
1. Whether you have been vaccinated or previously infected with the new crown virus;
2. The age of the infected person.
In the Danish study, the median age was 32 years because the outbreak of an early outbreak in Denmark was caused by a large gathering attended by young people. Secondly, the vaccination rate in Denmark is very high. 76% of Danes were vaccinated, of which 84% were vaccinated against BNT162b2 and another 14% were vaccinated with mRNA-1273. Of the Omicron infections reported this time, 83.1% were fully vaccinated or boosted.
In fact, full mRNA vaccination significantly reduces the severity of the condition in real-world COVID-19 patients.
In the face of Omicron, which is not milder and more contagious than Delta after infection, in addition to wearing masks and reducing travel, what we should do is vaccinate and strengthen vaccination.
Which vaccine is given to deal with the Omicron mutation strain?
This is a difficult question to answer. Because the Omicron mutant strain has immune escape from existing vaccines, there is also good news: the Omicron mutant strain still needs to bind to ACE2 on human cells through its spinous protein to infect humans [4]. This means that although there is currently no vaccine specific to the Omicron mutant strain, increasing the level of neutralizing antibodies in the human body through vaccination will still be effective in preventing infection or severe illness of the Omicron mutant strain.
That is, the level of neutralizing antibodies to the S protein of the new coronavirus in the human body is positively correlated with the protection against infection with the new coronavirus, including the Omicron mutant strain. The higher the level of neutralizing antibodies, the stronger the protection against infection.
And because after vaccination, the level of neutralizing antibodies gradually decreases with the time of vaccination, so strengthening vaccination has become a helpless choice. As a friend joked: the needle never stops.
In addition, different vaccine options apparently induce very different neutralizing antibody levels; BNT162b2 and mRNA-1273 induce significantly higher neutralizing antibody levels.
In particular, heterologous enhanced inoculation has very strong practical significance for improving the level of neutralizing antibodies.
Vaccination strategies for the Omicron mutant strain have not yet been published, but Paul Bieniasz, a prominent HIV virologist at Rockefeller University, has uploaded a high-quality Omicron study on vaccine escape on Twitter.
The researchers found that the original 2 doses of mRNA vaccine (BNT162b2 or mRNA-1273) and then enhanced vaccination with the BNT162b2 vaccine can significantly increase the titer (NT50) to reach 50% neutralization.
How high is it? In 2 doses of mRNA vaccination, serum NT50 against Omicron was increased by a factor of 38 after a third dose of intensive administration with BNT162b2.
That is, the third dose of the mRNA vaccine BNT162b2 can increase the serum NT50 of Omicron to 1,000-10,000, which is consistent with the original strain of NT50 after the second dose.
As a result, Paul Bieniasz's research shows that giving a third dose of the BNT162b2 vaccine is an important way to salvage the drop in titer after neutralizing antibody escape.
brief summary
By interpreting the detailed data behind the information in detail, we further confirm that:
1. In the real world, the severity of the disease of people infected with the Omicron mutation strain is indeed milder than before.
2. And the current study also shows that the severity of the disease after infection of the Delta mutant strain and the Omicron mutant strain is similar and milder than before. Even, the symptoms of the first 3 days after the infection were the same: runny nose, headache, fatigue (mild or severe), sneezing and sore throat.
3. According to the study of Los Angeles and South Africa, full mRNA vaccination is still effective in preventing severe disease in people infected with Delta mutant strain or Omicron mutant strain, which may explain the reason for the reduction of symptoms in patients with new crown infection.
4. Since the neutralizing antibody level is positively correlated with the protective power to prevent infection with the new crown virus, in the absence of AnOchron-specific vaccine, vaccination can induce a higher neutralizing antibody level is a priority method.
5. The study of Paul Bieniasz, a virologist at Rockefeller University, also confirmed this strategy, and they found that strengthening the third dose of the BNT162b2 vaccine is an important way to recover the drop in titer after neutralizing antibody escape.
Article author: Healsan, Source: Hanson Clinical Research, original title: "Omicron's condition after infection is milder than the previous strain?" Do I still need to get vaccinated? 》。