Pfizer and Moderna jabs could create 'years of immunity even against new strains': Spain's scientists evaluate findings

SCIENTISTS in Spain are discussing recent research that seems to show RNA-messenger vaccines against Covid offer long-lasting immunity, even against newer and more aggressive variants of the SARS-CoV-2 virus.

Immunologist Dr Matilde Cañelles of Spain's National Research Council (CSIC) considers the study to have been carried out 'very well' and that its results are 'very useful', but she does have a few minor criticisms, including how the sample size was small and should have included participants aged over 65, to compare these with younger adults.

So far, two RNA-messenger (RNAm) vaccines have been approved and are in use in Europe, the Pfizer-BioNTech and the Moderna – the AstraZeneca and Janssen are 'adenovirus' types, where a dormant virus is placed in a carrier fluid to stimulate the immune system into fighting it off.

The Faculty of Medicine at Washington University in San Luis, Missouri and the ICAHN School of Medicine at the Mount Sinai Hospital in New York, with teams led by immunologists Dr Rachel M. Presti and Dr Ali H. Ellebedy, have recently published the results of their research in Nature magazine, and conclude that these vaccines 'induce a robust response in germinal-centre B-cells' which 'allows the generation of solid humoral immunity'.

According to the Navarra Clinical Hospital medical dictionary, the germinal centre is a lymph organ structure where the process of 'maturing of antibody affinity' takes place – or a 'training ground' for B-cells to 'hone' their ability to recognise a virus.

Dr Cañelles says the sample size for the study could have been larger – only 14 participants were examined – although molecular biologist Dr José Manuel Bautista, also of the CSIC and faculty head at Madrid Complutense University, says even this small and apparently unrepresentative number 'might be enough' if 'statistical support is adequate', which is, he confirmed, the case here, and if the lymph node samples taken from the participants was 'correlated with samples of blood from the same area'.

But so far, and assuming the methodology has proven to be watertight, it appears RNAm vaccines may provide immunity for many years.

The same teams from the two US medical schools also published a study earlier this month which appears to show that patients who had recovered in full from Covid-19, even a very mild or asymptomatic incident of it, might be immune from it for life – although this does not explain a very small number of cases of people who have had it twice.

Dr Ellebedy and Dr Presti say 'long-duration' antibody-producing cells were detected in the bone marrow of recovered patients, and that these cells may possibly be there for the rest of their lives.

Length of time immunity is provided either through previous contagion or through vaccines is a key question the scientific community is asking at present – and a question constantly being revised after various new mutations of the SARS-CoV-2 have been detected in various parts of the world, including the UK, South Africa, Brazil, Perú, and now India.

These are now named after letters in the Greek alphabet rather than after the country they were first discovered in, to prevent stigma, so the 'Indian virus', which is gaining ground in Europe, is called the 'Delta', with a more severe variation on the same one referred to as the 'Delta Plus'.

Now, in France, this strain has spread from 10% of recorded Covid cases to 20%, whilst in Portugal, its presence among contagion numbers reported has risen fro 4% to 55% in a month; it is the cause of a slowdown in the UK's and Israel's coming out of lockdown, and led to another lockdown being imposed in Australia.

Dr Ellebedy and Dr Presti say their research has shown RNAm vaccines are effective against current known strains, and that those who have been fully inoculated may not need booster jabs 'as long as new variants do not mutate enough so as to be able to bypass the vaccine's efficacy'.

This comes in contrast to BioNTech's announcement in April that the Pfizer-BioNTech vaccine might need to be reinforced with a third dose nine months after the second.

As yet, the matter of whether adenovirus vaccines like the AstraZeneca and Janssen – so far the only one of these in use in Europe – provide similar immunity.

Dr Bautista of the Complutense says at present there are no other comparable studies to the research carried out into the Pfizer and Moderna vaccines, but that he would 'expect to see a similar outcome' for the adenovirus versions if there were.

Dr Cañelles, evaluating the research, said one of her main criticisms would be that the team did not study 'memory cells' at the same time.

“They analysed B-cell creation in lymph nodes and blood, which is absolutely great, and they've shown pretty high levels which would probably indicate that the cells would develop a good 'memory', but this has not been demonstrated – as the researchers themselves state in the article,” she says.

Much larger studies of the same type need to be carried out, she said, particularly contrasting the over-65s with younger adults 'to document the differences and generate a projection of how much cell memory is created in the former group'.

“This is what we're all concerned about right now, because it's now been several months since most of these were given their second vaccine dose,” Dr Cañelles argues.

“I would imagine studies of this type are being carried out, and when they are published, their results will be extremely significant.”