vaccination
Is blocking novel coronavirus
The most effective way
Since the end of 2020, Dalian has done a good job of vaccinating key population with new crown vaccine in batches according to the risk level.
At present, the vaccination work is progressing steadily.
In recent days,
Dalian Center for Disease Control and Prevention
Han Yinan, chief of the Immunization Program Section
On public concerns during the vaccination process
Carried on carding and answer
Ask questions
Qustions
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Answers
q
How long after Nova Coronavirus vaccine is administered can antibodies form protection?
a
Individuals differ in how sensitive they are to the vaccine, so the time it takes for protection to develop after vaccination also varies.
Usually about 10 days after the first injection, antibodies can be produced. However, due to individual differences, antibody titers vary between different people. Usually 14 days after the second injection, antibodies with high titers can be produced, forming effective protection.
q
How long is the protection period of Novel Coronavirus vaccine?
a
Ⅰ period, Ⅱ period clinical subjects are also continue to observe, the data obtained from already, can maintain at least 6 months above, to the world health organization specified requirements.
At present, the earliest vaccinated people have been monitored for more than eight months, the results show that it is still effective, with the extension of the observation period, the accumulation of research data, more than six months or even longer protection period may be confirmed.
q
Does Novel Coronavirus Vaccine Still Work?
a
Novel coronavirus vaccine is an inactivated vaccine, contains a variety of viral antigen components, is a broad spectrum, from the global different regions of the virus strains have a good crossover and neutralization effect, according to the current novel coronavirus mutation, reduce the effectiveness of the vaccine is not possible.
q
Novel Coronavirus vaccine How long after the first dose to get the second dose?
a
The first needle and the second needle interval is generally 14 to 28 days, the interval of three weeks to four weeks the best effect.
Immune persistence, antibody positive conversion level, antibody mean value and other indicators were better than the interval of two weeks.
q
What about Novel Coronavirus vaccine more than 28 days apart?
a
If a second dose of Novel Coronavirus vaccine is not received within 28 days after the first dose, re-inoculation is recommended as soon as possible within 1 to 2 weeks.
Novel Coronavirus vaccine immunization program currently used in China requires two doses, 14 to 28 days apart.
There is no clinical data on the effect of delayed second dose of Novel Coronavirus vaccine on its efficacy.
q
Novel coronavirus vaccine the second needle is not vaccinated OK?
a
Generally speaking, inoculate the first needle 10 days or so can produce antibody, but right now the antibody has not yet reached the neutralizing antibody titer that kills the virus, so inoculate the 2nd needle is very necessary.
q
Novel coronavirus vaccine after the first needle is inoculated, appear allergic reaction still can inoculate the 2nd needle?
a
A second dose is not recommended if a severe allergic reaction occurs after the first dose and cannot be ruled out as a vaccine cause.
It should be noted that local reactions such as pain, tenderness, redness and itching at the injection site and transient fever reactions do not belong to allergic reactions, and the second dose of vaccine can still be administered.
q
Can two injections of Novel Coronavirus vaccine be given from different manufacturers?
a
For now, the recommended two doses of Novel Coronavirus should be from the same manufacturer.
q
Do I have to wait 30 minutes at the vaccination site after receiving the Novel Coronavirus vaccine?
a
You must stay at the vaccination site for 30 minutes!
This is not a specific requirement for the Novel Coronavirus vaccine. Any vaccine should be given after 30 minutes of observation at the vaccination site.
q
Are there any serious adverse reactions to Novel Coronavirus vaccine?
a
At present, the adverse reactions detected are mainly local reactions, mainly pain at the inoculation site, while systemic reactions mainly include headache, myalgia and fever, etc., pain at the inoculation site and transient fever, etc., are not included in the category of serious adverse reactions.
The adverse reactions detected so far are far lower than those of common vaccines already on the market.
q
After being vaccinated with novel coronavirus vaccine, still use to wear a mask?
a
Novel Coronavirus vaccine takes a certain amount of time to produce protective antibodies, during which time there may be a risk of infection due to failure to obtain effective immune protection.
In individuals, the protection from vaccination is not 100%.
Before the formation of the crowd immune barrier, novel coronavirus is still easy to spread, so it is suggested that after vaccination, still want to maintain “wear a mask, wash hands frequently, often ventilation, less gathering” and other good hygiene habits, do personal protection.

Recently, reports about the mutation of the new coronavirus have continued to appear around the world, making the mutation of the virus the focus of attention. In the United Kingdom, South Africa, Brazil, Denmark, the Netherlands, the United States, Australia, Canada, Italy, Iceland, Japan, China and other dozens of countries, infections caused by variants of the new coronavirus have been discovered.

Source: Xinhua News Agency

Will these newly emerging variants of the new coronavirus affect the spread of the virus? Will it cause aggravation after infection? Will it affect the effectiveness of the vaccine and hinder the anti-epidemic process?

With these questions in mind, a reporter from the Science and Technology Daily interviewed Kazuo Kitasato, an expert in virology at the Department of Pharmacy, Nagasaki University, Japan.

What is virus mutation? Is it getting better and better?

Kitari said that the genetic information of life on earth is carried by substances called nucleic acids. Nucleic acids are mainly divided into two categories, one is DNA (deoxyribonucleic acid) and the other is RNA (ribonucleic acid).

Viruses are parasitic microorganisms that only infect cells that invade organisms and use the raw materials in the infected cells to copy their genetic information to their descendants.

According to the genetic material carried by the virus, it can be divided into two main categories, one is the genetic material of the virus in the form of DNA, we call it DNA virus, the other is in the form of RNA, we call it RNA virus .

RNA generally exists in the form of a single strand (single-stranded), and a small part also exists in the form of double-stranded RNA. The new coronavirus is a single-stranded RNA virus. RNA is composed of four ribonucleotides A (adenine), U (uracil), C (cytosine), and G (guanine).

In the process of RNA virus replication, because the general RNA virus lacks a proofreading mechanism, it is prone to a higher error rate during virus replication, so the virus is very prone to mutation. It can be said that mutation during the replication process is common to almost all RNA viruses. Viruses generally exist naturally in some wild animals, and they must be mutated to break through the isolation of species when they can infect people, and enter human cells from natural animal hosts to reproduce.

It can be said that mutation is a survival strategy of the virus.

The mutation of viruses is generally random and directionless. Not all of these mutated viruses survive. If the mutation of the virus cannot help the virus adapt to the environment, then the virus will be eliminated. Because mutation will also reduce the virus’s ability to infect or even disappear completely, most of the virus mutations may be harmful to the virus itself.

The mutation of the new coronavirus S protein directly affects transmission

Kitasato said that the new coronavirus mainly infects cells through the binding of the spike protein (S) on the surface of the virus to the angiotensin converting enzyme 2 (ACE2) receptor on the surface of human cells.

The mutation of the S protein of the new coronavirus may directly affect the infectivity and transmission ability of the virus, as well as the effect of the neutralizing antibody produced by vaccination. Therefore, our focus here on the mutation of the new coronavirus is mainly on the virus S protein.

The S protein of the new coronavirus is composed of 1273 amino acids. According to a paper report in the internationally renowned journal Cell, at least 106 mutation sites have been identified for the S protein of the new coronavirus.

The D614G mutation refers to the amino acid at position 614 on the S protein, which has been changed from aspartic acid (D) to glycine (G). This mutation was produced in Europe before January 15, 2020. Before March 21, the 614th position of the S protein of the global new coronavirus strain was mainly D. After that, the 614th mutation of G became the main epidemic strain. .

Most viruses currently circulating in the world are strains with this D614G mutation.

The 614G mutation site is located in one of the six key contact residues in the cell receptor binding domain (RBD) of the S protein. The emergence of the D614G mutation causes the virus S protein to have an extra Elastase cleavage site. The infection and transmission capacity of the D614G mutant virus released from the cell has been increased by nearly 10 times.

Although the D614G mutation enhances the virus’s ability to infect, the serum of the recovered patients can still fight against the mutant virus very well.

Virus variants found in the UK

Increased spread and higher lethality

The latest British report and the mutant virus discovered in the UK not only increased the infectivity of the virus, but also increased the virulence of the virus, which means that this mutant strain is more lethal.

Kitasato said that in January this year, the World Health Organization announced the emergence of a variant of the new coronavirus (mutant strain B.1.1.7) in the UK, which has spread to at least 60 countries around the world.

This mutant strain is mainly the N501Y mutant strain of the virus S protein. N501Y refers to the amino acid at position 501 of S protein changed from aspartic acid (N) to tyrosine (Y). This mutation site is also located in the six key contacts in the cell receptor binding domain (RBD) of S protein One of the residues, this mutation leads to an increase in the binding affinity of the virus S protein to the cell receptor, which in turn enhances the ability of the virus to enter the cell, resulting in a 70% increase in the infectivity of the virus. The S protein of the new British mutant B.1.1.7 contains D614G and N501Y mutations.

There are also South African variants (B.1.351, 501Y.V2) and Brazil variants (B.1.1.248), in addition to D614G, N501Y, E484K variants were also found.

The E484K mutation is also a key contact residue in the receptor binding domain (RBD) of the virus S protein. The E484K mutation of the S protein of the new coronavirus may cause the virus to escape the recognition of the immune system and invalidate the neutralizing antibody.

Source: Xinhua News Agency

Some studies have shown that the virus containing the E484K mutation reduces the neutralizing activity of the neutralizing antibody isolated from the vaccinated human body by more than 10 times. It can be seen that the impact of this mutation on the vaccine is not small, and we need to be very vigilant.

Kitasato said that no E484K mutation was found in the British virus variant. The South African mutant does not exactly match the British mutant, and they were produced independently. The Brazilian virus variant can be said to be almost a variant of the British and South African viruses.

Teenagers become susceptible, don’t let the vaccine go to waste

For viruses that invade the body, the body’s immune system recognizes the S protein of the virus and produces neutralizing antibodies to prevent the S protein from binding to its cell receptor ACE2. Lymphocytes capable of producing neutralizing antibodies will remember the recognition of the virus and provide long-term protection against the virus.

The main purpose of our vaccination is to stimulate our immune system to produce neutralizing antibodies so that we can prevent viruses from invading cells.

Vaccines against viruses are generally vaccinated twice. The first time is to priming the recognition of the virus by the human immune system, and the second time is to enhance or boost the production of neutralizing antibodies of the immune system to promote neutralization of production. Antibody lymphocytes produce memory.

During the two vaccinations, the human immune system will continuously optimize the antibody immune response to the virus, and generate more diverse and stronger neutralizing antibodies.

The rapid spread of the virus in the population will result in the survival of mutant virus strains that can evade the attack of neutralizing antibodies. These virus variants that evade neutralizing antibodies are also mainly concentrated in the field of RBD where the virus S protein binds to cell receptors.

Kitasato said that the mutation of the new coronavirus S protein has led to the expansion of infections worldwide. With the large-scale spread of the mutant virus in the community, children who are relatively unsuitable for infection are also vulnerable to infection, and more than 60% of the infected people, mainly young people, become asymptomatic or mildly infected, which has accelerated the rapid spread of the virus. Difficulties in epidemic prevention and control.

In countries where the epidemic situation is completely out of control such as the United States, India, and Brazil, new and different kinds of variant viruses (variants) will continue to appear.

If these countries that are out of control of the epidemic do not take more active and effective preventive measures for strict control, new virus variants will continue to appear and spread rapidly around the world, leading to the loss of all previous efforts to develop vaccines around the world and more precious lives. The virus swallows.

Therefore, all countries need to strengthen the detection of mutated viruses and make various precautions and preparations. The whole world must unite and work together to win this smoke-free war against the invisible enemy.

The report notes that U.S. virus tracking mechanisms lag far behind;

① The United States is reported to have lagged behind in many aspects of its response to the new pandemic — from the initial lack of testing to the current frantic and clumsy rollout of the new vaccine.
Lack of genetic monitoring is only one aspect;

② There is a reason why a more infectious variant of novel coronavirus was first discovered in the UK: there was a lot of genetic sequencing.
Since the outbreak, researchers in the UK have uploaded 151,859 sequences of new coronavirus individuals to the Global Initiative for Sharing Influenza Data, an international platform for sharing viral genome data.
Britain has the most shared genetic sequences in the world;

(3) If a more infectious novel coronavirus strain had first emerged in the United States, scientists might not have noticed it so quickly.
It is said that only 69,111 sequences have been uploaded to US laboratories so far, despite the fact that the US has a larger population than the UK, a cutting-edge biomedical research industry and tens of millions more Covid-19 cases.

(4) According to a report published by the National Academy of Sciences in July 2020, the current source of novel coronavirus genome sequence data…
In the US it is fragmented, often passive, reactive, uncoordinated, and underfunded.
It is insufficient to answer many pressing questions about the evolution and spread of novel coronavirus

Coronavirus infection or COVID-19 is still considered a respiratory infectious disease, but it can also cause serious problems in the central nervous system of the brain, with clinical manifestations of loss of smell and taste;
Some patients experience headaches, weakness and fatigue, and difficulty thinking normally, or “brain fog,” as if their head is broken.
No one knows yet, but it doesn’t seem to be directly related to the virus. Scientists are hoping to figure out soon whether the symptoms of the patient’s central nervous system are caused by SARS-COV-2 or something else, and how it affects brain function.
Are there any long-term “sequelae”?
Researchers at the National Institutes of Health’s (NIH) Institute of Neurology and Stroke have conducted the first in-depth exploration and study of brain tissue samples from patients infected with novel coronavirus.
The results of the study, published in the latest issue of the New England Journal of Medicine, suggest that the central nervous system symptoms of patients infected with novel coronavirus are most likely caused by the body’s widespread inflammatory response to viral infection and vascular damage, rather than by the brain tissue infected with novel coronavirus.
The researchers used a specially designed high-sensitivity MRI scanner to examine brain tissue samples from 19 dead patients.
The victims ranged in age from 5 to 73, and some had underlying medical conditions such as diabetes, obesity and cardiovascular disease.
The researchers focused on examining the olfactory bulb, which controls smell, and the brain stem, which regulates breathing and heart rate.
According to earlier reports, these two brain regions are thought to be most susceptible to novel coronavirus infection.
On the MRI images, these two areas do show unusual bright spots, but appear to be signs of inflammation, along with dark spots, indicating bleeding leakage (shown below) : closer inspection of these areas reveals that the tiny blood vessels are thinner than those in normal brain tissue.
This suggests that plasma proteins may leak into the space between brain cells under pathological conditions.
Intriguingly, the researchers did not detect evidence of novel coronavirus invading brain cells in these brain tissue samples, which may have triggered an autoimmune response, including T cells and brain microglia.
In fact, several viral tests (viral DNA or protein methods) showed no evidence of the presence of novel coronavirus.
The researchers cautioned that the findings were not final and needed further study.
But the results seen so far in human tissue are not consistent with those found in a mouse infection model.
NIH experts continue to explore how novel coronavirus affects brain tissue and triggers clinical neurological symptoms in patients.
With the more in-depth study of the way that novel coronavirus causes damage to the human body and the long-term consequences, people will gradually understand how this terrible and strange novel coronavirus causes disease, and finally find an effective treatment, perhaps it will be a few years.