Covid vaccine ‘weakened immunity’: How worried should I be?

Doctors and the UK’s Health and Safety Agency have warned that even people who have received two doses of the Covid-19 vaccine will die from reduced immunity. So how much protection do we have left?

Let’s fix some basics. The immune system has two main roles: to prevent us from becoming infected, and if that fails, to eliminate the infection from our body.

I want you to expand your imagination and imagine your immune system as a medieval castle.

Surrounding the castle is an army of hostile and ruthless coronaviruses desperate to break in.

Your first line of defense is the outer wall patrolled by the Legion of Archers. These are your body’s neutralizing antibodies. If they can stop the virus army, you won’t get infected.

But if the walls come down and the anti-antibody archers are evacuated, then the virus is there. He rushed into the castle and now you are infected.

However, all is not lost. There are still troops in the fortress at the center of the castle. These are your memory B cells and memory T cells. Like knights on horseback, they can rally armies, lead immune charges, and bring hostile invaders to their knees.

The Covid vaccine has trained your body’s troops — this includes antibodies and memory cells that respond to infection — to fight the coronavirus.

It’s no surprise that at least one of the defenders is going down. This happens after every vaccination or infection.

“There is good evidence that antibodies weaken over time, which leaves us with a distinct deficit,” said Professor Eleanor Riley, an immunologist at the University of Edinburgh.

The emergence of the Delta variant exacerbated the abandonment of these antibody archers from their posts. It just spreads and penetrates our bodies better – it’s like a new army is rising outside the walls, but this one brings cave trolls and siege weapons.

You may have noticed the consequences of this yourself – someone you know has been double vaccinated and still has Covid. Research, Not yet officially released, the AstraZeneca vaccine is estimated to reduce any form of Covid symptoms by 66% shortly after the second dose. Five months later, that number had dropped to 47 percent. For Pfizer, that number has risen from 90% to 70%.

This is clearly a problem for governments trying to control the spread of the virus. Whether a virus intrusion can do serious damage to a body trying to burn and loot you now depends on your second line of defense. However, vaccines can now prevent fewer people from going to the hospital.

Professor Adam Finn, University of Bristol and Government Vaccines Adviser, said: “We are seeing a large number of unvaccinated and vaccinated people entering hospital.

“Your protection against relatively mild infections declines faster, but your protection against hospitalization or death declines more slowly.”

The greatest risk of requiring hospitalization and even death is concentrated in older adults. Among the double-vaccinated people, the vast majority of deaths occurred in people over the age of 70. People in this age group are still far better off than people who share their birthdays but refuse to get vaccinated. As you can see, the risk is low in the younger cohort who have been double-vaccinated.

The constant rush of time ages every cell in our body, including those that make up the immune system. It becomes more difficult to train the immune system with vaccines as we age, and it is slower to respond when an infection arrives. Perhaps now that the antibodies have subsided enough, this vulnerability of the immune system is exposed.

“Older people may have some protection initially, but now that these antibodies have weakened, they may not have a second line of defence,” said Professor Eleanor Riley.

“Maybe that’s why we see old and infirm people dying despite two doses. »

In addition to this, health tends to deteriorate with age. Age has been one of the main risk factors for dying from a pandemic since the beginning of the pandemic. Older people are also the first to be vaccinated, so their immunity has more time to wane.

People with weaker immune systems at the start, including cancer and organ transplant patients, have a subtly different problem because their bodies don’t respond well to vaccines.

Dr Helen Parry, from the University of Birmingham, said: “Their antibodies declined at a similar rate to healthy people, but obviously they had a lower starting point.”

It should be noted that there are important differences between the Oxford-AstraZeneca and Pfizer-BioNTech vaccines Most life protection jobs in the UK.

“They seem to be fine in different parts of the immune system,” Dr. Parry said.

“The mRNA vaccine (Pfizer) is very good at building antibodies, and the AstraZeneca vaccine is very good at generating a T-cell response.”

To get back to the castle, Pfizer may be better at equipping the outer walls with archers to keep the coronavirus out, while AstraZeneca is better at the inner prison.

The good news is that even in decline, these are still very good vaccines. At the start of the pandemic, people dreamed of a vaccine that could cut deaths by 50%. Even in the declining and most at-risk age groups, this protection is still in the 80-90% range.

“Even the worst-case scenario, six months from now, is better than we had hoped when we designed these vaccines,” Professor Finn said. “They are still very good. »

The better news is that there is already evidence that the recall, which has affected more than 11 million people in the UK, is working.The data National Bureau of Statistics shows antibody levels – those early infection defenders – are in their old age.

“It’s a slam dunk to have an older person do it all over again,” Professor Finn said.

Now everyone is watching the numbers closely to see if it will bring down the number of cases and deaths.

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