Wednesday, December 08, 2021

Moderna or Novavax after AstraZeneca jab confers high Covid immunity, study finds

Combining different approaches to immunity does have intuitive appeal

The finding has important implications for lower-income countries that have not yet completed their primary vaccination campaigns, as it suggests you do not need access to mRNA vaccines – and therefore ultra-cold storage facilities – to trigger an extremely potent Covid-19 vaccine response.

The strongest T-cell response of all was generated by a dose of the AstraZeneca vaccine followed by a dose of the Novavax vaccine – both of which can be stored in a standard refrigerator.

The University of Oxford-led Com-Cov study set out to establish whether mixing and matching Covid-19 vaccines during primary immunisation schedules could be detrimental or beneficial to the overall immune response to vaccination. Such flexibility could be crucial to ensuring the rapid deployment of these vaccines in low- and middle-income countries, where vaccine supply may be inconsistent.

“What we’re seeing is that there’s a great amount of flexibility in the primary immunisation schedule,” said Prof Matthew Snape at the University of Oxford, who led the research. “Just because you’ve received dose one of a particular vaccine, doesn’t mean you have to receive the same vaccine for dose two.”

The study also bolsters confidence that using the Moderna vaccine as a booster dose in people who have previously received the AstraZeneca jab should result in high levels of neutralising antibodies and T-cells.

It follows separate data published last week suggesting that both the Pfizer and Moderna jabs can dramatically strengthen the body’s immune defences.

The 1,070 British participants received a first dose of the AstraZeneca or Pfizer vaccine, followed nine weeks later by a second dose of the same vaccine, or either the Moderna or Novavax jab.

Levels of neutralising antibodies were 17 times higher among those who received the AstraZeneca vaccine followed by the Moderna vaccine and four times higher among those who received AstraZenaca followed by Novavax, compared with those who received two doses of the AstraZeneca vaccine.

For those who started with the Pfizer jab, receiving a second dose of the Moderna vaccines jab resulted in 1.3 times as many neutralising antibodies than with two doses of Pfizer; while receiving Novavax as the second jab resulted in 20% fewer antibodies.

The study, published in the Lancet, also revealed differences in T-cell responses after combinations of different types of vaccines.

Vaccines that are mRNA-based, such as the Pfizer and Moderna jab, deliver a small piece of genetic code known as messenger RNA to human cells, instructing them to manufacture the coronavirus spike protein themselves; viral vector vaccines such as the AstraZeneca jab do the same thing, but use a harmless virus to deliver these instructions; whereas protein-based vaccines, such as the Novavax jab, deliver pre-made fragments of the spike protein alongside an immune-stimulating adjuvant.

While two doses of either the AstraZeneca or Pfizer vaccine resulted in similar numbers of T-cells, combining the AstraZeneca vaccine with a second dose of Moderna resulted in 3.5 times more T-cells. A second dose of Novavax resulted in 4.8 times more T-cells.

For the Pfizer jab, a second dose of Moderna resulted in 1.5 times more T-cells, while a second jab of Novavax resulted in fewer T-cells.

“It tells us that the RNA and the viral vector vaccines are doing something quite different when it comes to priming for the T-cell response,” said Snape.

Previous research on other viral vector vaccines, such as the Ebola vaccine, had suggested that a mix-and-match approach could lead to enhanced immune responses.

“What was a bit more surprising is that we didn’t see that so well with the RNA vaccines – especially when it comes to the T-cell response, said Snape. “RNA followed by a protein (Novavax) was slightly underwhelming when it came to the T-cell response.”

The study also examined the impact of these different vaccine combinations against the Delta and Beta variants. In all cases, there was a reduction in levels of neutralising antibodies, but there was very little drop-off in T-cell responses.

Both the UK’s Medicines and Healthcare products Regulatory Agency and the World Health Organization are currently considering whether to authorise the Novavax vaccine, and are expected to announce their decision within days or weeks. WHO authorisation would enable the vaccine to be delivered via the Covax initiative.

Dr Richard Hatchett, chief executive of the Coalition for Epidemic Preparedness Innovations, said: “This is extremely encouraging and valuable data on the potential to mix-and-match Covid-19 vaccines in primary immunisation schedules.

Knowing that a second dose of a different Covid-19 vaccine can generate a robust immune response is advantageous in helping the rollout of Covid-19 vaccines through Covax, especially in populations still urgently waiting for their primary immunisation or in those partially vaccinated.”


A UK doctor who was banned from using social media after posting a viral video questioning vaccines and masks has won a court case against a medical tribunal

Only on a technicality, ufortunately

The High Court on Friday did not weigh in on any of Dr Samuel White’s claims, but rather found the General Medical Council’s Interim Orders Tribunal made an “error of law” when it imposed restrictions on the GP’s registration after he was accused of spreading Covid-19 misinformation.

Dr White, who was a partner at a practice in Hampshire, posted a seven-minute video to Instagram in June explaining why he had resigned from his job, saying he could no longer work “because of the lies” around the pandemic, which he said had been “so vast” he could no longer “stomach or tolerate” them.

He claimed doctors and nurses had “their hands tied behind their backs” preventing them from using “safe and proven treatments” such as hydroxychloroquine and ivermectin, which he said were a form of “early intervention” in the disease.

Dr White questioned the safety of the Covid-19 vaccines, stated that 99 per cent of people who contract the virus survive, and raised concerns about false positives associated with PCR tests.

“Masks do nothing, by the way, they do absolutely nothing,” he said towards the end of the video.

“They don’t help you, they don’t help anyone else. Take off the mask.”

Dr White appeared on conspiracy theory podcast SGT Report in August where he elaborated on his views.

He described the mRNA vaccines as “genetic manipulation” and claimed the vaccination campaign was “one of the most egregious, heinous crimes that we’ve seen in modern history, perhaps in all history, because it’s happened on such a global scale”.

Later that month, the tribunal ruled that Dr White’s actions “may pose a real risk to public safety”.

The IOT imposed conditions on Dr White restricting him from “posting or sharing his views on the Covid-19 pandemic and its associated aspects on any social media platforms and requiring previous posts to be removed”.

“Dr White’s alleged means of imparting information in his capacity as a registered doctor, by way of social media platforms, to a wide and possibly uninformed audience does not allow for individual circumstances and does not give the opportunity for a holistic consideration of Covid-19, its implications and possible treatments and potential for reducing risk to health in individual circumstances,” the tribunal said.

Dr White’s barrister, Francis Hoar, argued the restrictions placed on his client were a “severe imposition” on his freedom of expression protected by Article 10 of the European Convention on Human Rights.

The matter was heard by the High Court last month.

In his ruling, Mr Justice Dove said the tribunal had failed to follow the procedures set out in the Human Rights Act 1998, which require that for any interim order General Medical Council must ask itself “whether or not the respondent would probably succeed at any subsequent tribunal hearing”.

“It is clear that the IOT did not direct themselves to the tests required,” he said.

“The decision of the IOT was clearly wrong and cannot stand … There was an error of law in the IOT’s decision based upon the nature of the conditions which they intended to impose and the impact which they had on Article 10. The decision was wrong from a purely procedural perspective.”

He stressed that it had not been “necessary for the court to express any opinion as to the merits of the opinions with which this case is concerned in order to achieve a resolution of the matter”.




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