Covid-19 vaccines: Your questions answered
With three Covid-19 vaccines having shown very positive results from clinical trials, a mass vaccination plan to defeat the coronavirus is now being planned.
Here’s what we know so far about the vaccines and how they will be rolled out.
How effective are the vaccines?
The Covid-19 vaccine created by Oxford University and Cambridge-based AstraZeneca has been shown to be up to 90 per cent effective if a half dose is followed by a further full dose, although it has been confirmed that this trial only involved under-55s, and resulted from an initial dosing error that could prove to be a very fortunate accident.
Two full doses led to 62 per cent efficacy. Combined, this gave an efficacy of 70.4 per cent, with protection conferred 14 days or more after the second jab. A further clinical trial using the half dose/full dose regime is planned by AstraZeneca.
The Pfizer/BioNTech vaccine has been shown to be 95 per cent effective, while the Moderna vaccine has 94.5 per efficacy.
How does the AstraZeneca/Oxford vaccine work?
The vaccine uses a harmless, weakened version of a common virus which causes a cold in chimpanzees.
Researchers have already used this technology to produce vaccines against a number of pathogens including flu, Zika and Middle East Respiratory Syndrome (MERS).
The virus is genetically modified so that it is impossible for it to grow in humans.
Scientists have transferred the genetic instructions for coronavirus’s specific spike protein – which it needs to invade cells – to the vaccine.
When the vaccine enters cells inside the body, it uses this genetic code to produce the surface spike protein of the coronavirus.
This induces an immune response, priming the immune system to attack coronavirus if it infects the body.
The vaccine was originally called ChAdOx1 nCoV-19 and is now known as AZD1222 by Cambridge-based AstraZeneca, which is in charge of its manufacture.
How do the Pfizer/BioNTech vaccine and Moderna vaccines work?
These are messenger RNA (mRNA) vaccines. Rather than weakened forms of the virus, they use only the virus’s genetic code.
An mRNA vaccine is injected into the body where it enters cells and tells them to create antigens. These antigens are recognised by the immune system and prepare it to fight coronavirus.
No actual virus is needed to create an mRNA vaccine. This means the rate at which the vaccine can be produced is accelerated.
How long will the protective effect from the vaccines last?
This is not yet known for sure, but a recent Oxford University study showed the body’s immune response to Covid-19 infection means someone is unlikely to be infected again for at least six months.
Sarah Gilbert, professor of vaccinology at the University of Oxford, said scientists were “optimistic” that the Oxford Covid-19 vaccine will offer durable protection. Other trials using the same technology showed a strong immune response maintained a year after vaccination.
What impact do the vaccines have on antibodies and T-cells?
The Oxford/AstraZeneca, Pfizer/BioNTech and Moderna vaccines have all been shown to provoke both an antibody and T-cell response.
Antibodies are proteins that bind to the body’s foreign invaders and tell the immune system it needs to take action.
T-cells are a type of white blood cell which hunt down infected cells in the body and destroy them.
Nearly all effective vaccines induce both an antibody and a T-cell response.
A study on the Oxford/AstraZeneca vaccine found that levels of T-cells peaked 14 days after vaccination, while antibody levels peaked after 28 days.
What about adverse effects or side effects?
The vaccines have been well-tolerated and there have been no serious safety concerns, known as ‘adverse effects’.
Oxford University said adenovirus vaccines like its Covid-19 vaccine have been researched and used extensively for decades. Some trial participants reported minor side effects such as injection-site pain, feeling feverish, or having muscle aches or headaches. These were less common in adults aged 56 and over.
A minority of Pfizer/BioNTech trial participants similarly reported sore arms, fevers and fatigue, with fewer than two per cent experiencing temperatures of 39-40C.
A slightly higher percentage of participants in the Moderna trial reported side effects including fatigue (9.7 per cent), muscle pain (8.9 per cent), joint pain (5.2 per cent), and headache (4.5 per cent).
How many doses have been ordered?
The UK government has secured 100 million doses of the Oxford University and AstraZeneca vaccine as part of its contract, enough for most of the population.
It has ordered 40 million doses of the Pfizer/BioNTech vaccine and seven million of the Moderna vaccine.
It has also secured access to:
- 60 million doses of a Novavax vaccine
- 30 million doses from Janssen
- 60 million doses of a vaccine being developed by Valneva
- 60 million doses of protein adjuvant vaccine from GlaxoSmithKline (GSK) and Sanofi Pasteur
When will a Covid-19 vaccine get regulatory approval?
This could happen very soon. Pfizer/BioNTech submitted their vaccine trial data to the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) on November 20 for it to consider authorisation. The MHRA confirmed on November 23 it had the data it needed.
According to The Guardian, hospitals could receive the first deliveries of the Pfizer/BioNTech vaccine between December 7 and December 9 to give to staff the following week.
In the US, the Food and Drug Administration (FDA) will meet on December 10 to determine authorisation in the US.
Also on Monday November 23, AstraZeneca said it would “immediately prepare regulatory submission of the data to authorities around the world” and will seek an emergency use listing from the World Health Organization for an accelerated pathway to vaccine availability in low-income countries.
On November 16, Moderna said it intended to seek emergency use authorisation (EUA) with the US FDA “in the coming weeks”, with final safety and efficacy data expected within two months.
How long will it take to roll out the vaccine?
The military and NHS staff are on standby to roll out a Covid-19 vaccine across the UK from December, once a vaccine has regulatory approval, but the government has said the “bulk” of the roll-out can be expected in January, February and March, helping the country to return to something like normality by Easter 2021.
It is thought the AstraZeneca/Oxford vaccine could be rolled out within weeks if approved.
Some four million full doses will be available in the UK by the end of this year with 40 million doses by the end of March, according to the firm. AstraZeneca plans to have 700 million doses of the jab globally by the end of March.
The government said it was in talks with Pfizer/BioNTech about how many doses of its vaccine would be available by the end of the year, but it has previously been suggested that 10 million might be available.
Health secretary Matt Hancock said: “If approval is granted, the NHS will be ready to deliver. An enormous amount of work has taken place to ensure we have the logistical expertise, transport and workforce to roll out a vaccine according to clinical priority.”
The Moderna vaccine could arrive in the UK next spring.
Meanwhile, if Valneva’s vaccine development is successful, it will provide 60 million doses in the second half of 2021.
The government then has options for more than 40 million doses in 2022, and a further 30-90 million doses, in aggregate, across 2023 to 2025.
How effective is the vaccine for different age groups?
There have been concerns that a Covid-19 vaccine will not work as well on elderly people as their immune systems are weaker – an issue that affects the annual flu jab.
However, data from the Oxford University and AstraZeneca vaccine trial suggests that there have been “similar” immune responses among younger and older adults, with Moderna reporting the same.
Who will get the vaccine?
The Joint Committee on Vaccination and Immunisation (JCVI) has examined data on who suffers the worst outcomes from coronavirus and who is at highest risk of death. Its interim guidance says the order of priority should be:
- Older adults in a care home and care home workers
- All those aged 80 and over and health and social care workers, though they may move up the list
- Anyone 75 and over
- People aged 70 and over
- All those aged 65 and over
- High-risk adults under 65
- Moderate-risk adults under 65
- All those aged 60 and over
- All those 55 and over
- All those aged 50 and over
- The rest of the population, with priority yet to be determined.
It is not confirmed yet whether children will be given the jabs, but they won’t be first in line given that they are less vulnerable to the virus.
How will a vaccine be rolled out?
Mass vaccination clinics have been proposed, with a number of venues suggested, including sports halls, leisure centres and NHS Nightingale Hospitals.
NHS leaders have said there will be “roving teams” deployed to vaccinate care home residents and workers. The vaccines require two doses, with a 21-28 day gap between doses.
How are the vaccines stored?
The Pfizer/BioNTech vaccine needs to be stored at -70C. The companies have designed packaging to keep it cold using dry ice, so they can be stored for 10 days without specialised freezers. These can be opened twice a day for less than three minutes at a time to maintain the temperature.
Pfizer/BioNTech’s vaccine will be flown from Belgium to the UK for distribution in trucks armed with GPS trackers and thermor sensors. They can then be stored in medical fridges for up to five days at 2-8C.
Meanwhile, Moderna’s vaccine will be manufactured in Switzerland and Spain. It has to be stored at -20C, which is achievable in a standard freezer. Refrigerated trucks will distribute the vaccine, which could then be kept in a standard fridge for up to seven days.
The Oxford/AstraZeneca vaccine is the easiest to store. It can be sent to GP surgeries in refrigerated vans or cool boxes before being placed in a vaccine fridge, away from light, at a temperature of 2-8C.
Do the vaccines need special storage conditions?
The Pfizer/BioNTech vaccine needs to be stored at -70C. The companies have designed packaging to keep it cold using dry ice, so they can be stored for 10 days without specialised freezers. These can be opened twice a day for less than three minutes at a time to maintain the temperature.
Pfizer/BioNTech’s vaccine will be flown from Belgium to the UK for distribution in trucks armed with GPS trackers and thermor sensors. They can then be stored in medical fridges for up to five days at 2-8C.
Meanwhile, Moderna's vaccine will be manufactured in Switzerland and Spain. It has to be stored at -20C, which is achievable in a standard freezer. Refrigerated trucks will distribute the vaccine, which could then be kept in a standard fridge for up to seven days.
The Oxford/AstraZeneca vaccine is the easiest to store, which makes it potentially of greatest use around the world. It can be sent to GP surgeries in refrigerated vans or cool boxes before being placed in a vaccine fridge at a temperature of 2-8C. Like other vaccines, it will also need protection from light.
Is there an alternative to an injection?
It is expected at this stage that vaccinations will be delivered by injection. But it is possible that other formulations, such as a nasal spray, could be developed in future.
Will I get to choose which vaccine I want?
That’s unlikely. Which vaccine is given is most likely to depend on availability.
Will the vaccines be safe for those who are immuno-compromised?
Some live vaccines are not recommended for those with a compromised immune system, such as transplant patients.
But the Oxford/AstraZeneca vaccine does not use a live virus.
Tests and analysis are ongoing to understand who should be given the vaccines, and whether they are suitable for those undergoing treatments for certain conditions like cancer or HIV.
How much do they cost?
The deals struck by the government have not been made public, but some reports have suggested the Oxford/AstraZeneca vaccine is relatively cheap, costing about £3 per dose.
AstraZeneca has pledged not to sell it for a profit, so it can be available to all countries.
Pfizer/BioNTech is also making its vaccine available not-for-profit, and is thought to cost around £15 a dose.
The Moderna vaccine could cost about £28 per dose, according to reports.
How many Covid-19 vaccine candidates are in development?
There are about 51 Covid-19 vaccines in various stages of development around the world,
As of November 23, only two have received any regulatory approvals - both in Russia - but there have been safety concerns over those because neither went through phase III clinical trials.
Sputnik V, developed by the Gamaleya Research Institute in Moscow, was approved by the Ministry of Health of the Russian Federation on August 11, while EpiVacCorona has also been granted regulatory approval without going through the full trial process.
For the rest of the world, the Oxford/AstraZeneca, Pfizer/BioNTech and Moderna vaccines are the frontrunners.
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