Answers to important questions about corona vaccine

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After receiving the Covid 19 vaccine, many people ask if they should receive booster doses in the future and if the booster dose should be the same as the first doses.

If you have received the Covid 19 vaccine, you may feel stronger because you know your immunity has increased, and you may be happy to be able to return to your normal life. Do you need an amplifier in the next few months? Does the answer to this question depend on which vaccine you received first? Like the flu vaccines designed to fight new species every year, do you need to get a new vaccine every year that is designed to fight new species?

According to a recent study published in the journal Nature, people who have received the mRNA vaccine (Pfizer / Bivantek or Moderna) may be immune, so they do not need a booster for years.

This is good news; But the question remains: Do we still have a defective immune system? And what if we use another type of vaccine-like Johnson or Astrazeneca ? (Covid Johnson and Astrazeneca vaccines use a harmless version of the common cold virus as a carrier to provide instructions for making coronary proteins in cells.)

Some scientists who have received the Johnson vaccine, which is a single dose, have said they use an extra dose of the Pfizer or Moderna vaccine because they are concerned that one dose may not be enough to control an infected delta species. Naturally, people ask if they should do the same. The US Centers for Disease Control and Prevention has not yet made any recommendations. In June, a working group from the Centers for Disease Control and Prevention said that there was still no evidence that a booster was needed.

Below are specialized answers to frequently asked questions about booster or booster doses of the Covid 19 vaccine. The answers are based on what experts already know and may change with access to new data.

What are amplifiers, and how do they work?

The booster vaccine is a way to increase the immune system’s response to pathogens. The booster does exactly what the primary vaccine does, where the goal is to increase protection (for example, by producing more antibodies). But if scientists want to protect you against a new strain that is very different from the version of the virus you were vaccinated against, they can change the booster. To understand this more clearly, it is helpful to review some basics of our body’s response to the virus.

The important point is that it is not only the antibodies that save us. Our immune system has more tools to defend the body: Deadly T cells find and kill infected cells. There are helper T cells that stimulate killer T cells, and they use another group of cells called macrophages to swallow infected cells and B cells. B cells are very important because they produce antibodies.

Certain types of B cells become memory B cells. These cells store instructions for producing specific antibodies. But they are not active. They hide in the spleen, lymph nodes, and perhaps the main site of infection, waiting for a signal to resume antibody production.

When you receive the booster vaccine, you signal to the B cells to reactivate. Now, whether this booster contains the main vaccine instructions or different instructions, it is useful. If it contains the basic instructions, it amplifies the signal and increases the number of antibodies produced. It retrains cells to detect the virus’s new features and produce antibodies if it contains modified instructions when exposed to a new species.

Which groups will need a booster for covid-19?

It should be noted that boosters are used only for people who have been vaccinated. Health officials will consider two more factors to determine if you should get a booster vaccine in the coming months.

First, are you a relatively young, healthy person who probably has a strong vaccine response? You are either old or have a weakened immune system to which you may not have such an answer. Amplifiers are more important for the second group.

Second, is there a new species different from the original virus and can escape the immunity you already have? “In the second scenario, everyone needs a booster,” says Ali Ellebedy, an immunologist at the University of Washington who co-authored a new study published in Nature. In other words, if a new species emerges that is completely different from what we have seen so far, we want the whole population to be covered by a wide range of boosters and the general vaccination to be resumed. “But if we control the species, it may not be necessary for everyone, and we will only need it for certain populations that are older or have a defective immune system,” said Ali Ellebedy.

The UK, which has approved all three vaccines used in the United States and the Oxford – Astrazeneca COVID-19 vaccine, plans to give boosters to people 50 and older before winter.

“You should expect boosters, like primary vaccines, to be distributed to priority groups,” said Dr. Krotica Kupali, an infectious disease specialist at South Carolina Medical University. “In my opinion, it should first be considered for people with the most immunodeficiency, such as transplant recipients and cancer patients,” he said.

Do you probably need a booster if you have received the Johnson & Johnson or Oxford – Astrazeneca COVID-19 vaccine (compared to Pfizer or Moderna)?

Studies on the body show that most people who receive mRNA vaccines, such as Pfizer or Moderna, may not need a booster for years.

The research team collected samples from participants’ lymph nodes, where immune cells were trained in the germ center structure to identify new pathogens. Approximately four months after the participants received the first dose of Pfizer or Moderna vaccine, the bud centers were still active, and the number of memory cells had not decreased. The researchers did not study the Johnson and Johnson vaccines. Ali Ellebedy told the New York Times that Johnson and Johnson might need reinforcements.

Monica Gandhi, a physician, and professor of medicine at the University of California, San Francisco, has criticized Ali Ellebedy’s conclusion. “I see no reason why the Johnson & Johnson or Astrazeneca vaccine should not cause the same strong immune response,” he said.

Ali Ellebedy explained that he did not think mRNA vaccines would produce more stable responses. Instead, the important issue is quantity: the number of antibodies produced and the number of cells that the body converts into memory cells. “There is a slight difference in the number of antibodies produced after two doses of mRNA vaccine,” says Ali Ellebedy. The amount of antibody produced by two doses of mRNA vaccine is greater than the amount produced by one dose of Johnson & Johnson vaccine. “This is also evident in terms of efficiency in experiments.”

The efficacy of mRNA vaccines in the prevention of Covid 19 is 94 to 95%. But the effect of Johnson and Johnson in clinical trials was 66 (all three vaccines were very effective in preventing hospitalization and death from Covid 19). “I think for those who have received a dose of the Johnson & Johnson vaccine, booster immunization should probably be considered,” said Ali Ellebedy. Especially with the help of one of the mRNA vaccines. »

But Johnson and Johnson announced on July 1 that there was no need to increase or increase the dose of the vaccine. The company said in a press release that it had conducted a small study showing that one dose of the vaccine provided adequate protection against Delta species. The results have not yet been published in prestigious journals. But it is very encouraging: one dose of this vaccine not only elicited a strong antibody response against the species, but the antibodies increased over time, but the company is testing to see if the two doses provide better protection.

Meanwhile, some experts, such as Peter Hotez of Baylor College of Medicine, said Johnson & Johnson vaccine recipients in the United States should wait for guidance. But other scientists concerned about the spread of delta species have received the Pfizer or Moderna vaccine, which they believe is not harmful and may be helpful. A virologist at the University of Saskatchewan in Canada, Angela Rasmussen, recently received the Pfizer dose in April after receiving the Johnson & Johnson vaccine. He asked Americans who received the Johnson and Johnson vaccine to ask their doctors about the possibility of a second dose.

But in general, based on the available evidence, Johnson & Johnson vaccine recipients do not need to worry about not receiving one of the mRNA vaccines as the first dose. “Kali, an infectious disease specialist, says:

People who have been vaccinated differently should not feel betrayed. Johnson, Johnson, and Oxford – Astrazeneca vaccines COVID-19 vaccine are both very good and, in most cases, provide good protection against Covid (except Astrazeneca against beta species). The most important thing to keep in mind is that vaccines have been shown to prevent number 19 in hospitalization and death.

Is it important that the booster be compatible with the initial vaccine you received?

If you have been vaccinated, the booster does not have to match the original vaccine. “They do not have to be the same at all,” says Gandhi. Recent data suggest that vaccine composition may enhance the immune response. According to a study not yet reviewed by experts, people who received one dose of the Oxford – Astrazeneca vaccine and then one dose of Pfizer a month later had a stronger immune response than those who received both doses of Astrazeneca vaccine. The vaccine combination strategy produced the same level of the antibody as the two-dose Pfizer vaccine. The combination of the two vaccines also produced a stronger T cell response that was more than twice that of the two doses of Pfizer.

Numerous studies have shown the benefits of vaccine combination, and no serious side effects have been reported so far. Of course, these studies were relatively small (so small that they could not detect them in the event of rare side effects). So some scientists say bigger studies are needed.

Is it possible to design a vaccine for circulating species each year, like the annual flu vaccine?

Covid-19 is unlikely to require an annual booster vaccine. Because Covid 19 is very different from infectious diseases such as the flu. The flu has a high rate of mutation. That is, it changes a lot from year to year.

The covid virus has 19 mutations in its spike protein region. But the changes have not been so great that we will probably need some booster every year. Buddy says:

Assuming there are no abnormalities (completely different), I do not understand why a person who has developed a healthy response to the vaccine will need a booster over the next two to three years.

Gandhi is even more optimistic. “It is not clear whether people with natural immune systems need a booster if they are fully vaccinated,” he said.

All vaccines elicit a good immune response; as mentioned earlier, there are antibodies, T cells, and B cells. Gandhi cites a 2008 study that found that people who had the flu as children and long ago in 1918 were still immune to B cells 90 years later. B cells can survive for decades.

But Gandhi sees it as a precaution against Covid 19, and since the new Coronavirus is still very new, it makes sense to get a booster once a decade.

But keep in mind that the species are not completely different. We cannot predict what type of virus will appear, and low vaccination rates worldwide increase species’ likelihood of infected species. In the case of vaccination, the risk is very high. But the virus has already taken us by surprise, and it may do so again.

Therefore, experts will continue to monitor the population and participants in the vaccine trial in the coming months and years. If vaccinated people find that they have been waiting for an infection for a long time after vaccination, it may signify that it is time to think about boosters.

Are Amplifiers Always Useful or Dangerous?

According to Ali Ellebedy, there is no scientific reason to think that boosting is harmful in any way. We have studied from the UK, showing that even a second dose of the Astrazeneca vaccine is helpful. The worst-case scenario is that this dose is useless. But there is no reason to think that this will hurt us.

Of course, experts do not think that all amplifiers are available for free. Gandhi says:

Vaccines are expensive, and insurance companies do not pay for them. People can handle it; But this should be based on scientific evidence, not fear or anxiety.

According to Gandhi, we must keep in mind that boosters increase the level of antibodies. But that does not mean we need higher levels of protection. There are T cells; there are B memory cells. So if they encounter a pathogen in the future, they will come out and fight it. There is no reason to increase the booster to increase the antibodies temporarily. Developed countries looking for boosters can prevent the development of first- and second-dose vaccines in developing countries.

Do people who have received the Covid Sinopharm vaccine need a booster?

Few studies have been published on the possible efficacy of the third dose of the Sinopharm (BBIBP-CorV) vaccine. But a small study from China found that a third dose of the Covid 19 Sinopharm vaccine resulted in a return to antibody levels that dropped a few months after the second dose. The study also showed that the booster increased cell-based responses to the Coronavirus. (Inactivated Covid 19 virus was used to make the Sinopharm vaccine.)

The findings, which experts have not yet reviewed, come as China has begun injecting the third dose into high-risk individuals because it fears that antibody levels will weaken over time. The Sinopharm vaccine is one of the main Covid vaccines in China and is used by some other countries.

According to the analysis of samples collected from health care workers, about five months after the second dose of Sinopharm, the mean concentration of antibody-neutralizing antibodies to the virus decreased to 70% of the observed levels four weeks after the dose. . One week after the third dose, the antibody concentration increased 7.2 times compared to the observed levels five months after the second dose.

The BBIBP-CorV vaccine study does not address how the antibody concentration affects the vaccine or how the antibodies react to different virus strains.

According to this article, cellular responses, another important part of the human immune system, also improved after the third dose of Sinopharm. The researchers said that the humoral and cellular responses to the third dose of the BBIBP-CorV vaccine were strong and rapid and that cellular responses could be important for long-term protection. But two foreign experts said it was not yet clear how the T cell response was related to the protection of Covid vaccines.

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