On 8 December the UK became the first country in the world to approve and administer the Pfizer/BioNTech vaccine. Nearly two months later, the UK has administered first doses of Covid-19 vaccines to 8 million people and has approved two additional vaccines.
As the death toll continues to rise and the entire UK population remains in a national lockdown, an effective vaccine strategy is critical. Mass vaccination is essential to any potential easing of the severe restrictions that have been in place since early January.
With the urgency and magnitude of the global effort to vaccinate billions, one aspect that cannot be overlooked is the amount of vaccine that goes to waste. Reducing vaccine waste should be a key aim of all rollout programmes to ensure this precious commodity ends up in the arms of as many individuals as possible and not in the bin.
What Is Vaccine Waste?
Vaccine waste is any vialled vaccine that goes unused. To some extent, vaccine waste is normal and to be expected. But the volume of vaccine waste is heavily dependent on vaccination rollout programmes, equipment and immunisation workers’ practices.
On 13 January, vaccines minister Nadhim Zahawi said NHS England had forecasted vaccine wastage to be around 10 per cent, but that the actual wastage rate was “well below that”. According to the NHS England service specification for Covid-19 vaccines, appropriate procedures must be in place to “…ensure that wastage is minimised and certainly does not exceed 5 per cent of the total number of vaccines supplied.”
Types of Vaccine Waste
The World Health Organisation (WHO) differentiates between two types of vaccine waste: closed vial wastage and open vial wastage.
Closed vial wastage occurs when there is physical damage to vials, vaccines expire before they are opened, or because vials are not kept at the necessary temperature during storage or transportation, rendering them unusable.
Open vial wastage generally occurs because of spillage, physical damage to open vials, expiry or because unused doses from multi-dose vials are thrown away.
Vaccines often come in multi-dose vials because they are more cost efficient and require fewer resources (i.e., fewer glass vials). Once a multi-dose vial has been opened, it has a relatively short shelf life of about six hours. Wastage rates tend to increase as the number of doses per vial increases.
The UK has approved three Covid-19 vaccines so far – Pfizer/BioNTech, AstraZeneca/Oxford and Moderna – all of which are manufactured in multi-dose vials.
The extra vaccine in each vial is called overfill, a common practice aimed at accommodating the occasional spill or slight inaccuracies. While excess vaccine is perfectly safe to use, excess doses from multiple vials cannot be pooled into one vial and then used. Similarly, leftover AstraZeneca vaccine cannot be combined with leftover Pfizer vaccine, and vice versa.
In the world of vaccinations, not all syringes are created equal. So, while extracting a sixth dose may be possible under ideal circumstances, using the sixth dose should be a bonus that vaccinators take advantage of where possible and not doses that the government depends on to reach its targets.
“Dead space” is the amount of vaccine left in the syringe when the plunger is completely pushed down, and low-dead-space syringes reduce vaccine waste as less substance gets stuck in the syringe. The use of these syringes and the ability to consistently extract a sixth dose could increase supply by up to 20 per cent.
Table 1 – Shelf life and dosage capacity of Covid-19 vaccines currently approved in the UK
Amount required per dose
Doses per vial
Unopened shelf life
Shelf life once opened
2.25ml of injectable material after dilution
Five doses comfortably, potential for a sixth dose
Six months at -80°C to -60°C. Five days when thawed and refrigerated between 2°C and 8°C.
After dilution, must be stored at 2°C to 25°C and used as soon as practically possible and within six hours.
4ml or 5ml, depending on manufacturer
Eight doses in the 4ml vial, 10 doses in the 5ml vial
Six months when stored between 2°C and 8°C.
Must be used within six hours of opening and stored between 2°C and 25°C
Seven months at -25°C to -15°C. Once thawed,
30 days when refrigerated between 2°C and 8°C.
Must be used within six hours of opening and stored between 2°C and 25°C
The two vaccines currently in use in the UK are the Pfizer and AstraZeneca vaccines. Government guidance has been amended to allow excess vaccine to be administered in both cases. The current guidance is as follows:
AstraZeneca: If another full dose is left over in a vial, it can be used; drawing up an additional dose should be subject to an individual health-care professional’s judgement, on a case-by-case basis.
Pfizer: The Medicines and Healthcare products Regulatory Agency (MHRA) amended their regulations to state that a sixth dose of the Pfizer vaccine can be drawn from each vial when possible. If a full sixth dose cannot be drawn, the excess vaccine must be discarded and cannot be combined with other vials of extra vaccine to reach a full dose.
For the Moderna vaccine, any unused vaccine or waste material is to be disposed of in accordance with local requirements. However, as the UK has yet to begin administering the Moderna vaccine, it is unknown how much vaccine will be left over after five doses and if that overfill will be enough to make up an entire sixth dose. Early anecdotal evidence from New York State public health officials suggests an extra dose may be extractable.
Best Practice from Around the World
In Israel, the global leader in number of doses administered per 100 people, more than 100,000 individuals aged between 20 and 40 years old have been vaccinated with leftover vaccines that would have otherwise gone to waste. At 24/7 vaccination hubs, people who are not members of priority groups can receive a jab when there is a lull in priority-group appointments. These empty slots tend to be later at night, showcasing the benefits of a round-the-clock service for the wider population.
Public Health Wales (PHW) has begun publishing data on the amount of vaccine wasted across the country. In total, 0.3 per cent of vaccines distributed in Wales have been wasted. The breakdown, as of 21 January at 5pm, was that 0.5 per cent of the Pfizer vaccine and 0.1% of the AstraZeneca vaccine had been wasted. PHW updates this information weekly and provides figures by individual health board as well as Wales as a whole.
The United States
The Biden administration reportedly recently reached an agreement with Pfizer that will allow the government to track which shipments are accompanied by low-dead-space syringes and which are not, according to the Independent. Vials shipped with regular syringes will be counted as five doses against Pfizer’s contract for 200 million jabs, and those accompanied by low-dead-space syringes will count as six doses towards contract fulfilment, highlighting just how valuable these special syringes are when attempting to extract an extra dose.
This specification will help avoid a situation where countries are being charged for six-dose vials but lack the ability to extract the sixth due to a lack of low-dead-space syringes. BD, the largest manufacturer of syringes in the world, has said that low-dead-space syringes are not as plentiful as regular syringes and a considerable effort to ramp up production is necessary to meet increasing global demand.
Figure 1 – Cumulative Covid-19 vaccination doses administered per 100 people
It is important to inoculate the priority groups set forth by government first, as they are most vulnerable to severe Covid-19 infections. However, we cannot be so rigid in our approach that valuable doses end up in the bin because there are not sufficient patients in place, priority or not, poised to receive those doses before they go to waste.
The UK has amended its regulations for the Pfizer vaccine to allow for a sixth dose to be drawn and administered if another full dose is available in the vial. This is a welcomed decision that will help reduce the amount of Pfizer vaccine that goes to waste. However, there are additional steps that can be taken, by any government or public health body, to further reduce the amount of wastage generated throughout the vaccination campaign.
Where possible, continue to safely use extra doses in multi-dose vials to make the most of vaccine supply.
Create “on demand” lists: As we set out in our paper on prioritising key workers, the government should create lists of available individuals ready to be contacted if and when there are opened vials that need to be used within a short period of time. These lists could be made up of local GP patients, key workers or staff that are ready for their second dose.
One way to do this is to develop an online registry that allows individuals to enter their location and register their interest at a local vaccination centre. At the end of each day, if a location has a surplus, they can notify registered individuals of available doses. If that individual cannot make it to the vaccination centre within a certain amount of time, they can opt out and the slot is then offered to someone else.
Maintain a steady flow of patients into vaccination centres to minimise the amount of vaccine left over at the end of each day.
Publish data on what percent of vaccines is being wasted – it is reported that NHS England has set this threshold at 5 per cent, but it is important to monitor this figure and adjust practices accordingly.