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– It is a well-known problem that vaccines may be less effective in most of the population, says vaccine expert Gunveig Grødeland, principal investigator in the Department of Immunology and Transfusion Medicine at UiO.
The immune system weakens with age, and older people are more prone to infectious diseases than younger people. They can have more serious illnesses and often do not respond well to treatment.
– Age-related changes in the immune system also lead to a reduced response to new vaccines, writes the National Institute of Public Health.
Therefore, vaccine candidates are discontinued.
Can be applied to corona vaccine
Grødeland tells Dagbladet that researchers don’t have a full explanation for why the elderly respond worse to vaccines. What they do know is that if the elderly have previously developed immune responses to similar viruses, the immune system tends to increase the production of the response to the earlier virus. This is again at the expense of the immune response, which would have been optimal for the new virus, explains Grødeland.
– The same will be expected to happen with more coronaviruses, because the elderly have been exposed to other coronaviruses before. Therefore, it should be borne in mind that the corona vaccine may be less effective in older people.
Known issue
Therefore, the immune system becomes less effective, because it forms a response to a virus similar to the one the body has been exposed to before, rather than attacking the new one.
Grødeland says the vast majority have been exposed to viruses from the coronavirus family, most of which cause cold symptoms.
– Another possibility is simply that the elderly, to a lesser extent, form an equally strong response to the virus. Therefore, to achieve protective levels, a higher dose of vaccine is required.
This is, among other things, a well-known problem when the elderly get vaccinated against seasonal flu every fall and winter, explains Grødeland.
– Influenza vaccines that are best for the elderly contain both the virus and an adjuvant (a substance that modifies and enhances the effect of other journaln.anm substances), which gives the immune system a little more boost, so that form a stronger response.
Kristin Greve-Isdahl Mohn, UiB Associate Professor and Chief Physician at Haukeland University Hospital, explains that the elderly generally react less to vaccines and may need a higher dose of vaccine and often two as well. dose.
– We see this, for example, through vaccination against influenza. Younger people tend to have a better immune response than older people. It’s actually a shame that those who need the vaccine most are the ones who may react the worst, he says.
We know this about the 2020/2021 seasonal flu
– Important target group
According to Nature, there is a separate team at Boston Children’s Hospital working specifically to develop a corona vaccine that is tailored for the elderly. Researchers are working in parallel to find an adjuvant to strengthen the vaccine.
– No vaccine will be as effective for the elderly as for the very young. It’s almost certain, says Matt Kaeberlein, a researcher and senior health specialist at the University of Washington.
– Could it be that the future corona vaccine will not work at all in the elderly?
– This is not a black and white scale, and there is often talk of gradients in which vaccines work a little, but not optimally. It is impossible to say exactly how well a corona vaccine will work in older people. This is a completely new vaccine against a completely new virus, says Grødeland.
Mohn emphasizes that a future corona vaccine must also show an effect in most of the population.
– Otherwise, it will not be approved. But the elderly may need a stronger dose. We’ll only see this when the data from the phase 3 trials is ready, Mohn says.
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– Depending on several
According to Mohn, when the initial vaccine was for the corona vaccine development, there were more than 100 candidates. The number has decreased considerably over time. At present, there are a dozen vaccines left and they have reached clinical trials in the so-called phase 3.
– There are very few left, but we depend on it being approved and on more people to the market, so that there are more options. It is good with several types, and it is very possible that one type is better for the elderly than others. But all this knowledge will come in the coming months, Mohn says.
Vaccine researcher and professor Shayan Sharif from the University of Guelph in Canada tells the BBC that very few vaccines produced today are produced for the majority of the population.
– In most cases in the last century, vaccines have targeted childhood diseases. When it comes to young, middle-aged and older adults, we don’t have much experience, he says.
The US Drug Agency said in June that the corona vaccine must work in at least half the population if it is to be considered effective. However, according to Nature, it is not certain that the majority of the population will reach the 50 percent goal.
Difficult after vaccine shock
A long way to go
However, from the moment the vaccine is approved, there is a long way to go before it can be widely distributed.
“From applying for approval until production can be scaled to many millions of doses, there is a long way to go,” says Mohn.
She anticipates that if all goes well, the first doses can be administered to Norwegian health personnel in early 2021.
– It’s a fantastic collaboration globally now, and it’s going with fast speed compared to the opposite, but there are no shortcuts when it comes to making new vaccines. They have to follow all the steps so that we are safe.