Thought of the Day - September 7 2021 - The Best Way to Top Up Immunity

We have been talking about the pros and cons of vaccines for some time. Vaccines are reducing deaths and hospitalizations (data from the US and UK suggest by as much as 70%), but seem to have little overall effect on transmission. Moreover, a number of countries are now seeing blood anti-bodies in well over 90% of their populations, yet cases continue apace. Thus, sorry to say, herd immunity is not going to happen.

A key challenge with all of the front-runner vaccines is not that their active ingredients don't work, but whether they have the dosing right. Too much and you risk having adverse reactions, too little and you may not improve resistance. With the time pressures to bring products to market, all had to make guesses, all had to make compromises. Most erred on the low side, and thus the needed to go for a double dose.

So now the question: given that SARS-CoV-2 with all its various variants is going to be around for the foreseeable future, how best to optimize the populations' immunity? There are now two main camps.

The first and most obvious is vaccine booster shots. In this way, any shortfall in dosing can be made up. In this way, as your body believes that infection has not gone away, the level of active antibodies (rather than just B and T memory cells) can also be boosted.

But there is a second, growing, thought. The best way to boost resistance, if we truly believe that vaccines significantly decrease the risk of complications, is to be exposed to SARS-CoV-2 and be naturally infected. Remember there are marked differences in your immune system after natural infection with coronavirus than after vaccination. The logic is that while vaccine immunity has a benefit, unfortunately, it is not as complete as when you are exposed to the virus itself.

One of the main differences is that only a small part of the virus is represented by the vaccine. This means only this part of the virus is recognizable to your body after you have been vaccinated. This incomplete pattern has a number of issues:

1. If your body does not have active antibodies, you may need a higher inoculum level to respond;

2. If the virus has any mutation in the part represented by the vaccine (in this case the spike protein), your body may not respond at all.

That aside there are also many other reasons to consider natural infection:

1. There is a whole different suite of antibodies (known as immunoglobulin As) in the nose and lungs, compared with those (immunoglobulin Gs) that we measure in the blood. The former is more important as a barrier to infection. Natural infection, because it is in the nose rather than a jab in the arm, may be a better route to those antibodies (this is one reason nasal vaccines are also being investigated);

2. SARS-CoV-2 is prevalent in society and so it is cheap and simple. No need to purchase vaccines, no need to set up repeat clinics, less need for lockdowns, passports and a host of other mitigating measures;

3. While of course natural infection has risk, so does vaccination - one in 10,000 experience severe side effects - while this is much less than from COVID, repeated jabs up this number. It is not just how your body reacts, it could be issues with vaccine quality control ( Thought of the Day - April 13 2021 - Vaccine Wars, Bi-weekly Update ) or issues with the administration of these repeat vaccinations ( Thought of the Day - March 25 2021 - Are We Doing Vaccinations Wrong? );

4. Rather than hoarding the supply of vaccines, by taking the natural method of topping up, vaccines could be redirected to countries that have severe shortages ( Thought of the Day - May 6 2021 - It's a Start ).

So which is better? Even asking the question bordered on heresy a year ago, when catching COVID for the first time could be deadly, especially for the elderly or people already in poor health. But now we're no longer starting with zero immunity as the overwhelming majority of people have either been vaccinated or have already caught the virus. It is now a serious question.

"We could be digging ourselves into a hole, for a very long time, where we think we can only keep COVID away by boosting every year," said Prof Eleanor Riley, an immunologist from the University of Edinburgh. Prof Adam Finn, a UK government vaccine adviser, said over-vaccinating people, when other parts of the world had none, was "a bit insane, it's not just inequitable, it's stupid".

The best argument I have heard is: if vaccines work, then we should not be worried about using natural infection to boost our bodies' immunity. Of course, if vaccines really don't work as well as advertised then we should instead be looking for alternative treatments.

Cheers

Cliff