Side-effects, storage and special warnings: Government publishes new guidance on Covid vaccine

‘No corners have been cut’ in approving vaccine, says UK drug regulator

The government has said that women should avoid becoming pregnant until at least two months after being vaccinated against Covid-19.

After approval was granted for the emergency use of the vaccine developed by Pfizer and BioNTech, new guidance has been released that provides precautionary warnings, information on side effects and recommendations for administration.

The Medicines and Healthcare products Regulatory Agency (MHRA) said “no corners have been cut” in approving the vaccine, adding that its review was “equivalent to all international standards”.

The two-dose vaccine has been shown to be safe and does not generate any serious side effects in humans, although some trial participants reported headaches and fatigue during the testing phase.

Certain specifics of the vaccine have yet to be studied in detail, prompting the government to release a series of precautions and special warnings for different groups in the population.

This is common practice for newly-approved products where more research is needed to determine its effects on pregnancy, fertility or lactation, and how it interacts with other drugs.

In new guidance issued on Thursday, the government has recommended that pregnant women do not receive the vaccine. Women have also been advised to avoid pregnancy for at least two months after receiving their second dose.

The government said it is also unknown whether the vaccine, named BNT162b2, has an impact on fertility.

Studies into how the vaccine interacts with other medicinal products have not been conducted, the guidance added.

Further information on the method of administration and distribution has also been provided.

Frozen vials of the vaccine will take three hours to thaw when placed in fridge conditions (2-8C), or 30 minutes in temperatures up to 25C.

After thawing, the vaccine should be administered by a healthcare professional and used within 6 hours.

Prior to injection, the vaccine solution must be diluted in its original vial with a small amount of sodium chloride, according to the new guidance.

When stored at -70C, doses vaccine will retain their integrity for six months. Supplies can be moved four times when at temperatures below -15C, the government added.

Transit of the vaccine at 2-8C can occur either in two journeys each up to 6 hours, or for a maximum of 12 hours in one sitting.

The guidance also outlined possible side effects that may be experienced after vaccination.

It said that one in 10 people may report pain at the site of injection, tiredness, muscle pain, headache and chills. One in 100 may feel unwell or experience enlarged lymph nodes.

Talk to your doctor, pharmacist or nurse before you are given the vaccine if you have:

• a weakened immune system, such as due to HIV infection, or are on a medicine that affects the body’s immune response
• a severe illness with high fever. However, a mild fever or upper airway infection, like a cold, are not reasons to delay vaccination
• a bleeding problem, bruise easily or use a medicine to inhibit blood clotting

The vaccine is also not recommended for children under 16 years of age.

Dr June Raine, head of the MRHA, said the regulator’s recommendation followed “the most rigorous scientific assessment of every piece of data so that it meets the required strict standards of safety, of effectiveness and of quality”.

Addressing concern that the organisation had rushed its review, Sean Marrett, BioNTech’s chief business officer, said: “The MHRA has asked the same level of detailed questions as any other agency and have focused on efficacy, the tolerance of the drug and the quality of production.

“These three elements are key elements to any vaccine that any regulator will look in detail at. I think the MHRA has been no different in that respect."