According to official estimates, two Covid jabs will still cut the Omicron death rate by up to 84%. But a booster can prevent someone from becoming ill twice as effectively.
Over the weekend, SAGE modelling was based on the assumption that Pfizer dosages offer 83.75% protection against hospitalisation or death due to the highly-evolved strain.
A 2-dose AstraZeneca vaccine course was shown to decrease the Omicron severe disease risk by 77.1 percent. Both vaccine brands are expected to decrease in effectiveness within the next three to six month.
The Government’s scientists advise that protection from AstraZeneca jabs may be reduced to 61.3 percent for Pfizer and 66.7 per cent for Pfizer.
A booster dose of Pfizer’s vaccine was estimated to top-up immunity to more than 93 per cent, regardless of which jab someone was originally given — providing a similar level of protection as two doses did against Delta.
The estimates were presented in modelling by the London School of Hygiene and Tropical Medicine (LSHTM) on Saturday and are based on lab studies looking at antibodies.
Since the Omicron strain was discovered, scientists have raced to find out whether existing vaccines are effective against it. It was feared that the spike protein, which contains 30 mutations, would make it virtually impossible to recognize for vaccines.
The current jabs are designed to kill the original Wuhan virus. Because the variant is still new, scientists are still basing their lab experiments on it. This may not be how the variant behaves in reality.
MailOnline spoke to Professor Paul Hunter who is an expert on infectious diseases from the University of East Anglia. He said that two shots would be sufficient to prevent severe illnesses. According to Hunter, South Africa’s Omicron ground Zero hospital data suggested that T cells were playing an important role in immunity.
According to Dr Simon Clarke at Reading University microbiologist, the decline in vaccine efficacy after two jabs remains ‘concerning. He told MailOnline: ‘Nobody ever expected Omicron to wipe out vaccine efficacy it was just a drop that was expected — and that in itself can do enough damage.’
Omicron can still leave 16 per cent at risk of being killed or in hospital even with an 84 percent protection against serious illness. This is three times more than with Delta.
These estimates of vaccine effectiveness were made by modelling at the London School of Hygiene and Tropical Medicine on Saturday. The models are based upon laboratory data that examine antibodies and not real-world data. It shows ‘vaccine effectiveness’ on symptomatic disease and hospitalisations/deaths from Omicron. These dots indicate the percentage of individuals in a 100-person group that are at risk for Covid. The study showed that boosters provided 93% protection from death and hospitalisation. If 100 people were vaccinated, seven would need hospitalization.
After the UK had reported 1,239 additional confirmed Omicron cases, the UK Covid alert level has been raised to level 4.
LSHTM found that AstraZeneca gave only 36.1% protection after 6 months of symptomatic Omicron, while Pfizer provided just 46.7 percent.
Based on early data, AstraZenca’s vaccine offers less protection than mild illnesses.
Comparatively, LSHTM models assumed that the booster Pfizer jab reduces the risk of symptomatic infective disease by 80.33%.
These neutralising antibodies studies, which measure Omicron in the blood of people vaccinated, were used by the team to estimate vaccine effectiveness.
Antibodies are an indicator of immunity but they’re only part of the larger immune response to virus. This also includes T- and B cells.
MailOnline was informed by Professor Hunter that the estimates in the paper provided a basis for optimism.
He stated that T cells are more important than antibodies and some evidence suggests T cell immunity may be better preserved between Omicron and older variants of Omicron.
The problem with this approach is that they use neutralising antibody estimates to estimate the results. This is accurate for symptoms and infection, but not so much when it comes to severe disease.
“So, there is reason to believe that they will be successful.” [the LSHTM’s] estimations for protection against hospitalisation and death might actually be better — even from two doses.
“There is some evidence that South Africa may be proving this.”
Despite hospital admissions rising in South Africa this year, data shows that patients coming into the hospitals with less severe illnesses are getting discharged faster.
Tshwane in Guateng Province is one of the epicenters of this new epidemic. Only 25% of those admitted for Covid since November had serious illness. This compares to 66% at the time of the Delta wave. South Africa now has an average of 40 Covid deaths per day.
Clarke advised against getting complacent with the statistics, saying that Omicron’s extremely infectiousness could be enough to overwhelm NHS.
No10’s experts have warned there could be an astronomical one million Omicron infections per day by the New Year — about 20 times more than the current rate.
Although scientists have different opinions on the probability of Britain reaching this level, Dr Clarke stated that: “We can’t ignore the transmissibility element.”
“If 1 million cases are being reported per day, then it would be expected that there will be a 20-fold rise in patients ending up in hospital. The NHS still has 10 times the patients despite taking half that number. Each day, around 800 Covid patients are admitted to UK hospitals.
Omicron has been reported to be much milder than other variants. However, Dr Clarke warns that jabs may not prevent infection from becoming so weak that the strain can cause’mass sick’.
“We may end up having a society or economy that stops and nearly stops not because people go to hospital, but because they are home sick and cannot work.
If true, the LSHTM paper’s estimate that two vaccine doses could provide as little as 36 per cent protection against symptomatic infection would put it below international vaccine thresholds.
When Covid jabs first came to fruition, the World Health Organization (WHO), stated that they needed to reduce risk by 50% in order for them be approved.
Professor Hunter argued that Britain’s latest turbocharged booster should be able to shield the country from an influx of patients, as it raises immunity far beyond that threshold. This is due to both natural and vaccine-induced immunity.
MailOnline was informed by him that he believed there is more protection than people think. South Africa seems to have done a good job. [fine]Even without the booster, they still have high levels natural infection. However we will need to wait a few more weeks before that can be confirmed.
LSHTM also considered a worse-case scenario in which weakening immunity to two jabs could provide as little as 45% protection against death and hospital admission.
Experts said that this is too optimistic and not likely to hold in real life. This scenario would mean that a booster could only provide 83.75% protection against serious illness.
Warwick University microbiologist Lawrence Young said that he is ‘cautiously optimist’ about boosters providing even greater immunity in real life and sufficient to avoid harsher restrictions.
He said that because of the delay between receiving a booster or developing immunity and getting it, light social restrictions were needed to prevent infections.
MailOnline spoke to him: “One of the challenges of super-charged booster campaigns is the fact that it takes approximately 10-14 business days for high levels of protective immune response.
“This highlights the importance of additional protective measures to prevent infection. I am convinced Plan B suffices.”