The Many Puzzling Outcomes of COVID

"It seems that the Oxford-AstraZeneca vaccine initially induces higher levels of T-cells than the mRNA vaccines."

"These T-cells are important for long-term immune memory and also for inhibiting virus replication and killing infected cells once an infection becomes established."

"Since the AZ vaccine is slightly better at inducing these T-cells, the implication is that it may provide longer-term protection against hospitalization and death."

"I think this is the point that Dr.Soriot was making."

Eleanor Riley, professor of immunology and infectious disease, University of Edinburgh

A woman receives her covid-19 vaccination booster jab, London, UK  Leon Neal/Getty Images

The chief executive of AstraZeneca, Pascal Soriot on Tuesday responded to a puzzle that scientists are mulling over. That while the defences of Europe are crumbling against COVID-19 with steadily mounting infections and deaths related to the coronavirus, Britain in contrast is managing to keep its serious cases relatively low in both hospitalizations and resulting deaths. The explanation he offered was that the Oxford vaccine produces a more durable T-cell response, which could be what is ensuring that older people in Britain are safer than their continental counterparts in the prevention of hospitalization and death.

Cases remain high in Britain, the country is struggling just like other parts of Europe, with rising numbers but hospitalization and death appears under a firmer control than elsewhere. The AstraZeneca vaccine has been hugely unpopular in Europe, viewed with great suspicion. Leading to France, Germany, Spain and Belgium restricting its use to those under 65 in the early roll-out stage. Suspicion was aroused that there was insufficient data to ensure it was effective in older people.

Now, Dr.Soriot suggests that data demonstrate the AstraZeneca shot offers long-term protection, with a response that appears more durable than the mRNA vaccines produced by Pfizer and Moderna. The data of which he speaks is not yet published and has not as a result been reviewed by any outside sources for whom it would be of consuming interest. T-cells, without a shadow of a doubt, have an important role to play in protection against COVID. Antibodies wane over time, but T-cells remain able to trigger powerful immune responses, and to directly destroy infected cells, as well to work against new variants.

Closed Christmas stands in the city centre, Vienna, Austria.  Lisa Leutner/AP/Shutterstock

The University of Birmingham in April found five weeks following a first dose people over 80 given AstraZeneca or Pfizer showed similar antibody responses. In the AstraZeneca  group, double T-cell response was observed. Along with the strength of the T-cell response held to be three times higher than for the Pfizer group. Oxford University researchers found, in mid-June a still robust T-cell response from AstraZeneca doses at six months that even with a single dose; antibody immunity drops aside.

Scientists from Oxford and Switzerland in July concluded that long-term immunity could be greater for adenovirus vaccines like AstraZeneca resulting from "cellular training camps" for T-cells that they create. On the other hand, in the long term, mRNA vaccines also produce strong T-cell responses, perhaps more so than AstraZeneca, according to more recent research. A new paper published in Nature found Pfizer produced close to a six times greater number of T-cells than AstraZeneca, some 18 to 42 days following the second dose.

Data collected in real-world situations consistently indicate that the mRNA vaccines gain a slight improvement in prevention of infection and avoidance of serious disease than does AstraZeneca, an inconsistency with claims better protection is provided by the Oxford vaccine. Another interpretation of the situation could be that Britain has had so much recent infection that COVID is near to becoming an endemic virus. In the United Kingdom the booster program began earlier so that at present over 12 million adults now have had their third, 'booster' dose, which is recognized as having prevented tens of thousands of deaths.

 

A wall in London commemorates people who died of COVID-19.  Credit: Toby Melville/Alamy/Reuters

More COVID Vaccine Complications

"One can never be sure, but it is more than coincidental."

"We are learning more about this every day."

"The medical community is very concerned and parents of young folks are very concerned."

"While these symptoms might be concerning, the outcomes are usually very benign, and it is still pretty rare."

Dr.Peter Liu, cardiologist, chief scientific officer, University of Ottawa Heart Institute

 

"Based on reports received, Canada is not seeing higher rates [of heart muscle inflammation] than would be expected in the general population [outside of a vaccine context]."

"Health Canada, the Public Health Agency of Canada, and the provincial and territorial health authorities are aware of these cases and will continue to monitor closely."

Health Canada 

An Israeli health worker administers a dose of the Pfizer-BioNtech Covid-19 vaccine to a woman at Clalit Health Services in January in the Israeli coastal city of Netanya. (Jack Guez/AFP/Getty Images)

 

Concerns are being raised in the medical community by a recently published report when Israeli scientists this week focused on findings that between one in 3,000 and one in 6,000 men between the ages of 16 and 24 had developed myocarditis (heart muscle inflammation) following both doses of the Pfizer/BioNTech COVID-19 vaccine in Israel.Though most cases turned out to be mild the revelation nonetheless has elicited concern by both parents and doctors.

While the general rate of myocarditis in any population is between one in 10,000 and one in 20,000 the rate reported among young men in Israel was 25 times higher. The report out of Israel represents the first extensive study making a link between rare instances of heart inflammation with COVID-19 vaccines. Similar cases have been reported elsewhere globally. "Canada is not seeing higher rates than would be expected in the general population", assured a spokesperson for Health Canada.

Despite which, Dr.Peter Liu, a leading Ottawa myocarditis specialist has seen two cases in recent months he attributes to vaccination. While the cases are yet under investigation Dr.Liu's belief is that there is a distinct connection with mRNA COVID-19 vaccines, a category both Moderna and Pfizer represent. One of the cases was that of a health professional who developed severe symptoms four days following vaccination with a Pfizer vaccine.

 

A 16-year-old in Tel Aviv, Israel, receives a dose of the Pfizer-BioNtech COVID-19 vaccine on 23 January.    JACK GUEZ/AFP via Getty Images

While myocarditis has resulted, albeit rarely, with the use of both Pfizer and Moderna, higher rates have been associated with a second dose. The U.S. has launched an investigation into the link with mRNA-based vaccines. Dr.Liu emphasizes that cases of myocarditis linked to inoculations with the mRNA vaccines are quite rare, with mostly mild symptoms, noting however, that they can persist to cause long-term side effects in more severe cases.

 Pfizer vaccine for COVID-19(AP Photo/Ted S. Warren)

The benefits, however, of vaccinating against COVID-19 vastly outweigh the minuscule likelihood of contracting myocarditis, he stresses, all the more so with the ongoing circulation of COVID-19 virus with more dangerous new variants beginning to take the lead in new outbreaks. Symptoms can include persistent chest pain, shortness of breath, dizziness or irregular heart rhythm, occurring within several days of being vaccinated. Symptoms which should prompt people to seek medical help.

"If untreated, severe cases can cause heart failure, stroke, rapid or abnormal heart rhythms, or sudden cardiac death", according to Health Canada. Dr.Liu was quoted stating that lowering the dose in young people might be "worth considering". The findings from Israel suggested the link between the Pfizer COVID-19 vaccination and heart muscle inflammation was at least statistically, a real phenomenon.