A UK Government virologist believes that some of the 300 next-generation Covid vaccinations could finally be effective in stopping people from spreading Covid.  

Professor Maria Zambon is the head of influenza and respiratory virology at the UK Health Security Agency. She said that the current crop of Covid vaccines should not be considered the “first generation”. 

It was hoped that the current Covid vaccines could be used to prevent infections and build immunity in the population.  

Herd immunity refers to having enough people in a population are effectively immune to a pathogen — meaning they are unable to catch and pass it on. 

Scientists believe that the herd immunity to Covid’s super-virulent Delta strain is not possible due to the fact that vaccines are less effective at stopping infection.

Professor Zambon however stated that this could change in the future.

‘We have well over 300 vaccines in development worldwide, the vaccines that we see in here are very much first generation vaccines,’ she said. 

‘It will be interesting to see in the coming years how next generation vaccines, or improved vaccines, can actually help on this question of prevention of infection, not just prevention of severe disease.’ 

The study found there was almost no difference in the Covid Delta variant viral load between the jabbed and unjabbed with both experiencing peak infectiousness, when they are most likely to pass the virus on to other people, three to four days after catching the virus. Where vaccination made a difference was after the peak with the jabbed able to better fight off the virus and recover quicker, with less severe symptoms.

The study found that there was almost no difference between the Covid Delta variant viral loads of the jabbed and the unjabbed. Both experienced peak infectiousness which is when they are most susceptible to passing the virus on to others. This occurs three to four weeks after they have caught the virus. The point where vaccination made a difference was after peak, when the jabbed were better able to fight the virus and recover faster, with less severe symptoms.

UK Health Security Agency head of influenza and respiratory virology Professor Maria Zambon said the Covid vaccines we have now are the 'first generation' and that more effectives ones could be in the pipeline, with more than 300 new types of jab in development

Professor Maria Zambon, head of influenza and respiratory virusology at the UK Health Security Agency, said that the Covid vaccines currently available are the ‘first generation’. More effective ones are in the pipeline. There are more than 300 types of jabs in development.


Herd immunity refers to indirect protection against an infectious disease. It is achieved when a population is either immune through vaccination or has developed immunity through previous infections.

It basically means that once someone has some form of immunity, it reduces their ability to spread a disease among the population.

A person who has antibodies, either from previous infections or vaccines, acts as a “barrier” to the virus.

If there are enough “barriers”, the disease can’t spread to a large population.

A new virus, like Covid, can spread almost without barriers and can cause a pandemic.

The World Health Organisation states that it supports herd immunity through vaccination and not allowing disease to spread through any population segment.

MailOnline was told by a specialist that Covid is here for the long-term and that it is important to reach a threshold of ‘herd immunity’.

This keeps the virus at an endemic level, which is where a disease is present in the population but not severe enough to cause significant social disruption.

The expert said that keeping Covid within the threshold of herd immunity, which can fluctuate in winter when diseases like flu and coronavirus spread quickly will ensure it is kept at a manageable level.

Research has shown that the current Covid vaccines increase the antibody response to the virus. This greatly reduces the chance of someone becoming seriously ill. 

Professor Zambon was speaking following the publication of a new study she contributed to showing that both vaccinated and unvaccinated people have the same potential to infect people if they catch Covid.

The study, published in The Lancet Infectious Diseases, found that regardless of vaccination status people who caught Covid had the same viral load until it peaked at three to four days after infection.

The viral load refers to how many viruses are in a substance. In the case of Covid, this refers to how much is in the upper respiratory tract (mouth, nose, throat), and nasal cavities. 

However, people who were vaccinated had a better experience after the viral peak. Their bodies were more able to fight the virus.

The discovery suggests that vaccinated people can spread the disease as easily as those who are not vaccinated, but they are less likely than the unvaccinated to contract the virus.

The UK has ordered more that 400 million doses eight different vaccines. Only four of these have been approved in the UK by the Medicines and Healthcare products Regulatory Agency. 

The latest study did not examine differences in vaccine types. However, the virus load of the 133 participants who were tested had been measured and they had received both AstraZeneca as well as Pfizer jabs.

Although the idea of “herd immunity” was popularized by Government during the pandemic, it was deemed unethical. The idea that the virus would ‘rip’ through the population to create natural immunity was not acceptable to the public. 

The term resurfaced in public consciousness with the launch of the vaccine drive in the early part of this year. Ministers hoped that the combination of jabs as well as natural immunity would provide the protection necessary to stop the spread of the virus.

Early data showed that vaccines against the Alpha variant were around 80 percent effective. Experts believe that herd immunity could be achieved before Boris Johnson’s death.

But the emergence of the more transmissible Delta variant — which reduced the vaccines’ effectiveness against transmission to as low as 40 per cent — meant scientists were less optimistic it could be achieved.

Initial estimates suggested that at most 70% of the population must have some form immunity in order to meet the threshold. However this target was not met as the virus continued to spread despite high levels vaccines. 

The Government has ordered 60million doses of Novavax, which the MHRA is currently reviewing. Pfizer is the most-ordered jab in the UK, with 135million due to arrive in Britain by next year. Some 100million doses of AstraZeneca have been ordered, along with 60million doses of the jab made by GSK. Meanwhile, the Government has requested 50million CureVac vaccines, 20million Janssen and 17million Moderna injections. But only four jabs have been approved in the UK: AstraZeneca, Pfizer, Moderna and Janssen

The 60 million Novavax doses ordered by the Government are currently being reviewed by the MHRA. Pfizer is the UK’s most-ordered jab, with 135million expected to arrive in Britain next year. AstraZeneca has been ordered for 100 million doses. GSK has also ordered 60million doses. The Government has also requested 50million CureVac vaccines and 20million Janssen injections. Only four jabs were approved in the UK: Janssen, Moderna, Pfizer and AstraZeneca

If a vaccine could reduce the person’s Covid infectiousness within that three to four-day window, then the idea of “herd immunity” might be possible. 

But Professor Lockdown, Neil Ferguson, of Imperial College London, the key Government advisor, whose modelling prompted the first lockdown last March, who also contributed to the study, and was also speaking at the briefing, said herd immunity could be achieved in just a few weeks.

‘Will we ever reach a stage where immunity stops future transmission? I mean that may happen in the next few weeks if the epidemic’s current transmission peaks and then starts declining then we have, by definition, reached herd immunity,’ he said.

Yesterday’s decline in Covid cases in Britain was the fourth consecutive day. Another 43,941 new infections were reported by the Department of Health, a decrease of 10.6 percent compared to last Wednesday’s total of 49,000. 

Daily cases have been declining since Sunday, after reaching a three month high last week. Government ministers today claimed that the chance of ministers activating winter ‘Plan B’ is less than 20%.

However, the number of people who die from Covid continues to rise. Today, there were 207 new deaths. It was 15.6 percent higher than the 179 recorded last week.

According to the most recent data, there was a 2.9% increase in hospitalisations week-on–week on Saturday. They reached 894, a rise of 869 over the previous week. 

However, Professor Ferguson said herd immunity is not a destination, but a state that can be both achieved and lost.   

‘It is not an all or nothing thing, herd immunity is having an enormous effect right now on dampening transmission due to the huge amount of vaccination which has gone on and the large number of people which have been infected already,’ he said. 

‘But it is not going to be a permanent thing. The immune system deteriorates over time and is not perfect so transmission can still occur.

Professor Ferguson said that the UK could be at the peak of infection in the coming weeks. 

‘Too early to say whether we have reached a peak, mainly because this week is half-term week and so we know lots of people go on holiday and testing patterns are different than usual,’ he said.

‘We will have to wait at least a couple of weeks, if not closer to three to be sure, but there are some encouraging signs in terms of the dip in case numbers.’

He stated that there was uncertainty in the predictions about the peak in the next few week, but that it was dependent on the UK’s Covid booster Jab programme. 

‘If isn’t peaking now then most of the SAGE modelling out there would suggest that it should peak so long as we keep getting boosters into people’s are and achieve a reasonable high, 90 per cent or so, coverage of boosters,’ he said. 

‘Then we should start to see a sustained decline in the coming weeks, but there is a lot of uncertainty in the modelling in all three groups that contributed into that exercise going into SAGE, about when exactly the peak will be.’

The UK’s Covid booster campaign has been criticised for being sluggish with calls to speed it up so half a million jabs a day are dished out.

On Monday, approximately 6.4million boosters were administered. As such, 244,992 people volunteered for the top up injection.

Another important finding was that double-jabbed people still have a 1 in 4 chance of contracting Covid through an infected household member, according a Neil Fergusson study.  

This is true even if infected person was fully vaccinated, according to Imperial College London researchers.

But the risk to unvaccinated household members was even greater, with a 38 per cent chance of catching the virus from infected household members. 

The scientists were “surprised” to discover that protection offered by Covid vaccines began to decline three months after the first dose.

They claim that the findings make it more important than ever to have booster jabs.