The committee has reviewed the latest available evidence, including the current COVID-19 infection rate, the scale and pace of the vaccine programme and modelling of the timing and size of any third pandemic wave.

This has been considered alongside the latest advice from the Medicines and Healthcare products Regulatory Agency (MHRA) on extremely rare cases of concurrent thrombosis (blood clots) and thrombocytopenia (low platelet count) following the first dose of the Oxford/AstraZeneca vaccine.

The chances of a younger person becoming seriously ill with COVID-19 get smaller as infection rates increasingly come under control in the UK.

Considering this alongside the portfolio of vaccines available in the UK in the coming months and taking a precautionary approach in relation to the extremely small risk of thrombosis and thrombocytopenia following the first dose of the Oxford/AstraZeneca vaccine, the JCVI has advised a preference for adults aged 30 to 39 without underlying health conditions to receive an alternative to the Oxford/AstraZeneca vaccine – where available and only if this does not cause substantial delays in being vaccinated.

This follows the decision on 7 April to offer a preference for adults aged under 30.

The COVID-19 vaccines are highly effective and have been shown to substantially reduce the risk of death, severe disease and transmission of infection.

Over 34 million people have received a first dose so far. The vaccine programme is estimated to have prevented over 10,000 deaths by the end of March.

Adverse events following the Oxford/AstraZeneca vaccine are extremely rare and, for the vast majority of people, the benefits of preventing serious illness and death far outweigh any risks.

Up to 28 April 2021, the MHRA had received 242 reports of blood clotting cases in people who also had low levels of platelets in the UK, following the use of Oxford/AstraZeneca vaccine. These numbers are very small compared to the millions of people who have received the vaccine. The overall incidence of case reports of thromboembolic events with low platelets after first or unknown doses was 10.5 per million doses.

The majority of these extremely rare events occurred after the first dose.

Everybody who has already had a first dose of the Oxford/AstraZeneca vaccine should receive a second dose of the same jab, irrespective of age, except for the very small number of people who experienced blood clots with low platelet counts from their first vaccination.

Getting the second vaccine dose is very important because it further increases the level of protection against COVID-19.

Professor Wei Shen Lim, COVID-19 Chair for JCVI, said:

Safety remains our number one priority. We have continued to assess the benefit-risk balance of COVID-19 vaccines in light of UK infection rates and the latest information from the MHRA on the extremely rare event of blood clots and low platelet counts following vaccination.

As COVID-19 rates continue to come under control, we are advising that adults aged 18 to 39 years with no underlying health conditions are offered an alternative to the Oxford/AstraZeneca vaccine, if available and if it does not cause delays in having the vaccine. The advice is specific to circumstances in the UK at this time and maximises use of the wide portfolio of vaccines available.

The COVID-19 vaccines have already saved thousands of lives and the benefit for the majority of the population is clear – if you are offered the vaccine, you should take it.

As a precautionary measure, anyone who has the following symptoms from around 4 days to 4 weeks after vaccination is advised to seek prompt medical advice:

  • a severe headache that is not relieved with painkillers or is getting worse
  • a headache that feels worse when you lie down or bend over
  • a headache that is unusual for you and occurs with blurred vision, feeling or being sick, problems speaking, weakness, drowsiness or seizures
  • a rash that looks like small bruises or bleeding under the skin
  • shortness of breath, chest pain, leg swelling or persistent abdominal pain