30 Aug 2021 Various topics : waning immunity, side effects and Belgian COVID research

Mon, 08/30/2021 - 17:26

Dear colleagues,

The core papers of this episode are brought to our attention by colleague Patrick Smits (on waning immunity) and colleague Kevin Ariën (on recent contributions from Belgian consortia).  Thanks both!

I add some information on related topics.

But first the mixed news from Brussels from a Flemish newspaper:


With just 50 % vaccinated subjects you see the consequences: those who are vaccinated are protected against severe disease and those who are not are filling up the ICU.  Brussels is a  breeding place for the virus  to the rest of the country.   

Waning immunity to vaccines?

In the preceding episodes, we have seen that a combination of changing behavior in vaccinated people and the evolution of the delta variant have already resulted in increasing breakthrough, hence apparently decreasing vaccine efficacy against infection, bur still good protection against severe disease.  

The next question is whether/when will immunity, elicited by vaccination, start to decrease

Ep 168-1:  A study from Israel illustrates waning efficacy for all age groups with increasing time since vaccination.  Whether this is due to decreased immunity is not 100 % sure, as it is difficult to control for confounders such as exposure (e.g. more relaxed social contacts), the shift from alpha to delta etc.

Ep 168-2: Patrick Smits discusses the issue of possible waning immunity (also in UK) in a wider context.  Worth reading in detail and therefor attached for your convenience

Ep 168-3:  A discussion by Helen Branswell.  Some of her interviewees are pessimistic and fear that we will see vaccinated subjects getting severely ill and die rather soon. 

Ep 168-4:  Hengcong Liu et al in medRxiv 23 July calculates the needed coverage in Shanghai for herd immunity and concludes:

  • With a vaccine efficacy of 74 % (expected for the inactivated or Adeno’s) a coverage of over 90 % is required.
  • Taking into account the higher infectivity of novel variants, more efficacious vaccines and equally high coverage are needed.  


The consensus on the “third jab” remains that it is useful for vulnerable people with weak immune system, but not (yet?) as a “booster” for the general population.  We should first try to vaccinate “everybody” with a regular regimen.

Clearly, this becomes a “wicked problem”….

Two overview papers/comments on real or feared side effects

Ep 168-5: Heidi Ledord in Nature 26 Aug 2021: A comment on the Vaccine-Induced Thrombotic Thrombocytopenia (VITT) by Astra-Zeneca and Janssen.  The etiology is not yet clear and the condition remains extremely rare.

Ep 168-6:  Emily Willingham in Scientific American 23 August 2021

  • Studies so far have not linked the vaccines with problems related to pregnancy, menstrual cycles, erectile performance or sperm quality.
  • The evidence does show that COVID-19 can involve problems in all of these areas.

The question is whether this “evidence” will be able to eradicate the wild stories on internet that make many young people hesitate to get vaccinated.

Recent papers from Belgian COVID research consortia

Ep 168-7: Annemieke Smet at al. in JCI Insight provide a groundbreaking insight indeed in a neglected aspect of innate immunity: the mucin system.

The graphical abstract gives a picture of what is called “dynamic interactions”

In addition, it was shown that the polymerase inhibitors remdesivir, favipiravir as well as the immunomodulating antibodies baricitinib (inhibiting JAK-STAT) and tocilizumab (inhibiting IL6-receptor)  are able to reduce SARS-CoV-2-induced mucin expression, either directly or indirectly in cell culture.

Clearly, these “association studies” lead  the way for prospective studies i.e. mucin mRNA measurements at baseline, during infection and postinfection, and concurrently also non-COVID-19 age-matched cohorts … to elucidate the prognostic/predictive potential of this peripheral mucin mRNA signature for COVID-19.


Ep 168-8: Joachim Mariën in Family Practice

  • The seroprevalence of primary health care physicians remained stable between June and September (4.6–5.0%), increased significantly from October to December (8.1–13.4%). 
  • At that time it was slightly but significantly higher than the general population, suggesting that the occupational health measures implemented provided sufficient protection when managing patients.


Ep 168-9 : Timothy Devos et al in Eur Resp J: Early transfusion of 4 units of high neutralising-antibody-titre convalescent plasma in hospitalised COVID-19 patients does not reduce mortality or the need for mechanical ventilation.


Now I have to focus on FWO scholarships for a few days…


Best wishes,