1. Another booster? Why actually?
The new booster campaign, planned from the end of September, is to be extra well prepared for the coming winter immunologically, is the simplest answer.
After all, protection against the coronavirus gradually decreases after vaccination or an infection. This is because the immune system is scaling down its vanguard of guards (the so-called ‘antibodies’), but also because the virus itself has mutated: from delta to omikron.
Those who were boosted six months ago are still protected for about 70 to 80 percent against hospitalization, but hardly any more against getting the omikron variant, it turns out. from the overviews. A booster boosts those percentages to around 90 percent protection against serious illness, and around 70 percent against common contamination.
The new shot is therefore primarily intended as a refresher course for the immune system: wake up! ‘We are still very much in the active phase of the epidemic,’ says professor of vaccinology Cécile van Els (RIVM, Utrecht University). ‘So you have to ask yourself: can you protect especially vulnerable people even better?’
2. What exactly does the new tailor-made vaccine entail?
The two boosters likely to be approved by the EMA on Thursday, from moderna and from Pfizer, give the immune system a good picture of what the original coronavirus looks like. But in addition, they also show the protrusions of the omikron variant – version BA.1, to be precise.
Whoever takes the ‘bivalent’ (bivalent) jab will then make about one and a half times as many antibodies against the omikron variant as someone who would take the classic jab, according to laboratory research. The extent to which this actually translates into better protection remains to be seen. But it is obvious that the protection against omikron will be better.
The bivalent vaccine will also offer roughly one percent more protection against hospitalization than the classic booster, a study shows just published, rough estimate. That doesn’t seem like much, but could quickly translate to dozens of hospital patients in the event of a major revival of corona.
The fact that a slightly different version of omikron – BA.5 – is already circulating and that the original coronavirus is no longer circulating, makes little difference, thinks Van Els. ‘You force the immune system to take another look: where are the differences, and where are the similarities? In this way you slowly but surely move towards a solid, increasingly general immunity.’
The US and Great Britain have already decided to allow the bivalent injections on the market. If the EMA also does the same on Thursday, the Netherlands will use the bivalent jabs in the upcoming booster campaign, a spokesperson for the Ministry of Health, Welfare and Sport confirms.
3. Wouldn’t that hurt, all that booster in a row?
In theory yes. Too many vaccinations too close together can make the immune system lazy. This is not harmful, but it is impractical: new boosters then simply have less and less effect. However, it is far from that yet, emphasizes Van Els. ‘We see in all studies that each new injection still provides a lot of added value.’
The effect of the third shot in particular surprises many immunologists: ‘We see that many people suddenly reach a completely different, higher level of protection. People with a somewhat weaker immune system, in particular, often produce very good levels of antibodies after shot number three.’
Incidentally, Van Els is not in favor of ‘repeating endlessly, every three months’, she emphasizes. But: ‘The immune system is made for repeated exposure. Think of bacteria that you ingest, or colds that you get over and over. Perhaps we will gradually move towards a more balanced situation, in which you use vaccination less often and only offer it to very specific groups.’
4. Are the new seasonal shots safe?
make about it experts have little to worry about. After all, the vaccine composition itself is unchanged: strings of genetic material packed in fat vesicles, which instruct cells in the body to temporarily produce the spines of the virus. The only thing that has changed are some letters in the genetic material, so that the vaccine also produces the omikron protrusions.
The vaccines, like the seasonal flu shot, have also been tested on a small scale, on several hundred test subjects. They reported no side effects other than those already known: a sore arm, some fatigue, a day of discomfort. The dose is also lower than that of the basic vaccine.
5. Does the seasonal booster have enough added value?
There is debate about this among experts. In the US, two members of the FDA drug reviewer even voted against the development of the variant vaccines. An entirely new shot might actually deter people from getting it, the critics fear, while boosting with any vaccine is now just as important: it increases the amount of antibodies by a factor of eleven. Ultimately, the new jab could thus lead to a declining, instead of a higher protection of the population.
In addition, the new injection will not prevent the immune system from letting go of its highest state of alert after a few months. People are then still protected against serious illness, but can still contract the virus again. “If the goal is to prevent infections, updated vaccines will also be of little value,” said one of the opposing FDA members, pediatrician Paul Offit. this week against trade magazine science.
Van Els points out the advantage. Omikron has some new tricks up its sleeve for escaping antibodies, and the new shot tells the immune system how to get around them. ‘By offering a slightly different spike protein each time, another class of B and T cells is added,’ she says. Those are the cells that ultimately have to ‘remember’ what coronaviruses look like. ‘So you broaden and strengthen the defenses with every exposure.’