People may need a fourth Covid jab less than a year after getting a booster, Pfizer's boss said today amid concerns about the rapid spread of the super mutant Omicron variant.
Dr Albert Bourla, chief executive officer of the pharmaceutical giant, today said he previously thought a fourth jab may be needed a year after a third injection.
But the emergence of Omicron may mean people require a total of four injections faster, he said. However, three doses 'will give very good protection' against Covid this winter, Dr Bourla added.
It comes after Pfizer yesterday warned two doses of its vaccine won't prevent Omicron infections, but 'may still offer protection against severe disease'. Independent scientists believe the same will be the case for other vaccines, such as AstraZeneca's.
But preliminary laboratory tests showed a third Pfizer vaccine triggers a 'more robust' antibody response to Omicron, similar to two doses against previous strains of Covid — suggesting the boosters will thwart the mutant strain.
The company — which has earned billions through the pandemic after making an effective jab — also revealed millions of doses of a new version of its vaccine tailored to the mutant strain won't be ready until March if the current crop of jabs fail in the real world.
And Dr Anthony Fauci, the US's top infectious disease expert, said the definition of 'fully vaccinated' in America will change to require a booster dose as well. And health officials are already investigating the potential need for a fourth dose of the vaccine after people receive their boosters, he said.
Meanwhile, two separate studies released yesterday showed vaccines appear to work better than expected against Omicron, which is quickly spreading in Britain and has made No10 resort to its 'Plan B' to save the NHS from being overwhelmed this winter.
But top Government advisers have warned that the NHS could still face severe pressure this winter from Omicron if it is definitively proven to be more transmissible, simply because of the sheer number of people who would get infected.
UK officials hope the country's booster roll-out to all adults — which Boris Johnson pledged to deliver by the end of January — and implementing Plan B will save the NHS in the face of the oncoming wave of Omicron, which leading scientists believe will be dominant by Christmas.
But less than half of over-18s in Britain have had a booster, meaning 23million who will be eligible by the end of January are yet to get their third dose.
Pfizer's results are based on a laboratory study using the blood of 20 people, who were either double-jabbed three weeks earlier (left) or triple-jabbed one month earlier with its vaccine (right). The graph shows antibody levels against different strains of the virus: Wuhan (green), Beta (blue), Delta (orange) and Omicron (red). The results showed the third dose triggered a 25-fold jump in antibody levels against Omicron from 6 to 154. Pfizer said this equates to a 'high efficacy' based on data on other variants. The level of neutralising antibodies against Omicron after three jabs was 154, a similar level to those made against the Wuhan strain after two jabs. But the figure was 60 per cent lower than levels seen for three doses against Delta (339)
Researchers at the African Health Research Institute (AHRI) found the Pfizer vaccine triggers forty times fewer antibodies capable of fighting the Omicron variant compared to an older version of the virus. The graph shows that antibody levels — scientifically known as geometric mean titer (GMT) FRNT50 — among 12 people jumped to an average of 1,321 when they were exposed to an older strain of the virus (D614G). But when scientists tested their blood against Omicron, antibody levels dropped to an average of 32, marking a 41.4-fold decrease. Six of the volunteers were double-jabbed with Pfizer (orange), while the other half were double-jabbed with Pfizer and had previously tested positive for Covid. People previously infected with Covid had the most protection
A separate study by researchers at the Karolinska Institute in Stockholm, Sweden found that while there is a drop in the body's ability to neutralise Omicron it is not seen in everyone and is a smaller drop than feared. Their findings are based on recent blood samples from 17 people in Stockholm (shown in middle graph), compared to 17 hospital workers who were previously infected with the original Wuhan strain (shown in right graph). The middle and right graphs show the participants antibody levels when exposed to the Wuhan variant (WT) compared to Omicron. The left graph shows the average antibody levels recorded among both groups when exposed to the original strain (purple), Delta (blue) and Omicron (green)
The above map shows the ten areas that have the most confirmed Omicron cases in England, according to the UK Health Security Agency. West Northamptonshire is the country's hotspot for the mutant strain, although eight in ten areas on the list are in London
The above graph shows the cumulative count for Omicron cases across the UK. Scientists say that there is no difference at present between England and Scotland's outbreaks
No10 announced last week that it plans to ramp up the booster programme to 500,000 jabs per day and offer a third dose to all 53million British adults by the end of January to shield against the incoming wave. But the scheme already appears to be stalling with less than 330,000 delivered across Britain yesterday and just 380,000 administered each day on average. At the current rate, all eligible adults will not be boosted until February 10
Speaking to CNBC, Dr Bourla said real world data will show whether current vaccines offer good protection against Omicron.
But he said: 'I think we will need the fourth dose. I’ve said that multiple times.
'With the previous [variants], I was projecting that that will be on 12 months after the third dose.
'With Omicron, we need to wait and see because we have very little information. We may need it faster.'
'But for right now, the most important thing it is that we have winter in front of us.'
He said a third dose 'will give very good protection' and allow countries to 'go without concerns through the winter'
'I think we should be in very good safe to control the winter based on what we say right now,' Dr Bourla said.
'And then if there is a need for something different better, we will be able to have in months,' he added.
His comments come after Pfizer announced results yesterday based on a laboratory study using the blood of 20 people, who were either double-jabbed three weeks earlier or triple-jabbed one month earlier with its vaccine, which Britain is using for its booster programme.
The results showed the third dose may provide a 'more robust protection', triggering a 25-fold jump in antibody levels.
Pfizer, which manufactured the jab with German partner firm BioNTech, said the levels equated to a 'high efficacy' based on data against other variants.
A booster jab offered a boost in antibody levels that are 'comparable to those observed' for the original Wuhan virus after two doses, the company said.
The level of neutralising antibodies against Omicron after three jabs was 154, compared to 155 against the Wuhan strain after two jabs.
But the figure was 60 per cent lower than levels seen for three doses against Delta.
Experts cautioned that a drop in antibody levels doesn't necessarily translate into vaccine efficacy, but merely gives an indicator as to what can be expected.
Announcing its results yesterday, Pfizer also said booster injections appeared to increase a specific kind of T cell, which is thought to play a crucial role in staving off severe illness.
Antibodies attack the virus and stop it attaching to and infecting the body's cells.
If the virus manages to breach that defence, T cell protection identifies them and stops them spreading further.
The company will collect data on whether the antibodies remain at that level in the months after a booster dose, with immunity known to wane slightly over time.
It will also monitor real-world data to better understand how its jabs perform against the strain.
Discussing the results with CNBC today, Dr Bourla said: 'The best way to see it is.... The first dose builds a wall but it is not very high.
'The second dose builds a wall on top of the first that’s really high and now and it was very good for other variants. Now it looks like the Omicron has the ability to jump over this wall.
'The third dose takes the wall very high and should stop, expect to stop the Omicron.'
Meanwhile, blood samples among double-jabbed people showed a 25-fold reduction in antibody levels against Omicron, compared to the original strain.
Three weeks after the second dose, antibody levels stood at 155 against the Wuhan stain, while it dropped to 6 against Omicron.
A sharp reduction was also seen against the Beta variant, which triggered six times less antibodies (36) than the original strain.
He said the Omicron variant 'came as a surprise' because it has three times as many mutations as experts were used to seeing on variants.
The UK's decision to rollout boosters three months after the second dose is 'the right way to go' to ensure better protection over the winter, Dr Sahin said.
It is 'very clear' that three doses of Pfizer's vaccine are needed to provide protection against Omicron, although scientists do not yet understand why two doses do not provide sufficient protection, he added.
Pfizer's chief executive officer Albert Bourla said: 'Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it's clear from these preliminary data that protection is improved with a third dose of our vaccine.
'Ensuring as many people as possible are fully vaccinated with the first two dose series and a booster remains the best course of action to prevent the spread of Covid.'
Dr Sahin added: 'Our preliminary, first dataset indicate that a third dose could still offer a sufficient level of protection from disease of any severity caused by the Omicron variant.
'Broad vaccination and booster campaigns around the world could help us to better protect people everywhere and to get through the winter season.
'We continue to work on an adapted vaccine which, we believe, will help to induce a high level of protection against Omicron-induced Covid disease as well as a prolonged protection compared to the current vaccine.'
Pfizer began developing a Covid vaccine to specifically targets the Omicron variant on November 25, which it can dish out tens of millions of doses from March 2022 if the current crop of jabs are not providing sufficient protection.
Earlier versions of the new vaccine will be ready for pre-clinical trials in January.
The company said all of its vaccine production — which will reach 4billion doses in 2022 — could be switched to the new version of the vaccine, depending on the spread of Omicron.
More than 800 Omicron cases have been spotted in the UK since the virus was first identified in South Africa.
Boris Johnson last night signed off on Plan B, declaring people should once again work from home where possible. In a gloomy Downing Street press conference, he said ministers would extend the use of masks and introduce Covid passports for nightclubs.
In a move that bounced No10 into activating its back-up plan, SAGE warned ministers Omicron hospitalisations may breach 1,000 a day in England by the end of the year without tougher restrictions to stem the spread of the super-mutant Covid variant.
Meanwhile, a pre-print study, which is yet to be peer-reviewed, found Omicron could seemingly dodge many vaccine-triggered antibodies.
However, the study only looked at antibodies, which are just one part of the immune response that fights off the virus. Although they are normally a reliable indicator of immunity.
It is not clear whether the reduced number of antibodies will translate into lower protection against severe illness, hospitalisation and death among those who catch the strain.
Professor Alex Sigal, a virologist at the African Health Research Institute (AHRI) who led the study, tweeted that the results of the study are 'better than I expected of Omicron'.
He noted there is a 'very large drop' in protection from Pfizer compared to other variants, but those who previously had Covid and are vaccinated were more protected against the variant.
And Professor Jonathan Ball, a virologist at the University of Nottingham, noted that while 'the amount of virus killing observed in the lab is reduced markedly – up to 40-times reduction – there is still measurable virus neutralisation, especially in those who were vaccinated and previously infected.'
'This group effectively mimics what we would expect in people who had had two doses of vaccine plus a boost,' he said.
Professor Ball added: 'Whilst we do not fully understand what protective immunity looks like, the data should give us reassurance that the vaccine will still offer protection.
'The other thing to remember is that many of the vaccines also generate T cell immunity and we think that this will be less impacted by the high level of mutations that omicron has.
'Whilst this reduced antibody immunity might mean more people can be infected and have mild symptoms, I am still confident that the vaccines, especially after a boost, will still protect from serious disease.
'That's why we still need to get the message across, get vaccinated, get boosted, even if you have been infected before.'
A separate study by researchers in Sweden found that while there is a drop in the body's ability to neutralise Omicron, it is not seen in everyone and is a smaller drop than feared.
Scientists at the Karolinska Institute in Stockholm found there was an average seven-fold drop in neutralisation potency among 17 blood donors.
Benjamin Murrell, an assistant professor in computational biology, virology and immunology and one of the researchers behind the study, said this is 'certainly worse than Delta' but is not 'as extreme as we expected'.
He said Professor Sigal's study reported a 'much more substantial average reduction' but noted 'what is common is that neutralisation is not completely lost for all samples, which is positive'.
It comes as the US's top infectious disease expert Dr Fauci said the definition of 'fully vaccinated' in America will eventually change to require a booster dose as well.
The director of the National Institute of Allergy and Infectious Disease (NIAID) said that the change is unlikely to happen in the next week, but he expects it to happen at some point in the future.
He also said the health officials are already investigating the potential need for a fourth dose of the vaccine after people receive their boosters.
Meanwhile, Covid cases appear to be peaking in the South African province at the epicentre of the Omicron outbreak, data suggests.
The Gauteng province has seen a meteoric rise infections since mid-November, when the first cases of the highly-evolved strain started appearing — jumping from 58 to 11,703 as of yesterday.
Professor Christina Pagel, a mathematician at University College London who has been following the outbreak, said infections have been increasing at a rate of around 25 per cent per day in the region since November 15.
She said infections over the last four days have dipped below this trend, suggesting cases may be rounding off their previous exponential rise.
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