Half of people in the UK now have antibodies against coronavirus, either through infection or vaccination, tests conducted by the Office for National Statistics (ONS) show.
According to the most recent coronavirus infection survey, an estimated 54.7% of the population in England would have tested positive for antibodies to coronavirus from a blood sample in the week ending 14 March 2021.
Quick GuideVaccines: how effective is each one?
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Pfizer/BioNTech
Country US/Germany
Efficacy 95% a week after the second shot. Pfizer says it is only 52% after the first dose but the UK’s Joint Committee on Vaccination and Immunisation (JCVI) says this may rise to 90% after 21 days.
Doses Clinical trials involved two doses 21 days apart. The UK is stretching this to 12 weeks.
Oxford/AstraZeneca
Country UK
Efficacy 70.4% 14 days after receiving the second dose. May have up to 90% efficacy when given as a half dose followed by a full dose. No severe disease or hospitalisations in anyone who received the vaccine.
There have been concerns it is less effective against the South African variant of the coronavirus, and that a rare type of blood clot can be a side effect.
Doses Two, four to 12 weeks apart
Moderna
Country US
Efficacy Phase 3 trial results suggest 94.1%.
Doses Two, 28 days apart
Novavax
Country US
Efficacy Phase 3 trials suggest 89.3%.
Doses Two
Janssen (part of Johnson & Johnson)
Country US
Efficacy 72% in preventing mild to moderate cases in US trials but 66% efficacy observed in international trials. 85% efficacy against severe illness, and 100% protection against hospitalisation and death.
Doses: One, making it unique among Covid vaccines with phase 3 results so far
Sinovac
Country China
Efficacy Unclear. Researchers in Brazil have found the efficacy of the Chinese vaccine to be as low as 50.4%, whereas Turkish officials reported interim data from trials showing efficacy was 91%.
In Wales, an estimated 50.5% of the population would have tested positive for antibodies to coronavirus, while the figure for Scotland was 42.6% and for Northern Ireland 49.3%.
The study was conducted based on blood test results taken from a randomly selected subsample of individuals aged 16 years and over, which are used to test for antibodies against coronavirus. It points to a success in the UK’s vaccination programme, with 30 million people having received at least one dose.
The infection survey also found variation in antibody positivity between regions in England. Over 60% of individuals in the north-west have antibodies for coronavirus, compared with 50.3% in the south-east.
Age is also a factor in increased antibodies. More than 76% of people aged 70 years and over have tested positive for Covid-19 antibodies in the UK. The higher levels of antibodies observed in older age groups reflect the high vaccination rate in older people.
Of those aged 80 years or older, in England, 86% tested positive for coronavirus antibodies. In Wales it was 79.2%, Scotland 74%, and in Northern Ireland 76.4%.
The ONS is careful to draw a distinction between testing positive for antibodies and having immunity. In their report they state antibody levels can vary and sometimes increase, but are still below the level identified as “positive” in tests.
The figures show a rise in the number of people having protection against coronavirus – up from approximately a third of people testing positive when levels were measured at the start of March.
The UK has recorded 56 further deaths and 4,040 new cases, according to the latest update on the government’s dashboard. Coronavirus-related deaths are falling at the rate of 35% while new cases are falling by 7.9% week on week.
Other figures released by the ONS on Tuesday confirm that more than 150,000 people have died from coronavirus in the UK.
Based on mentions of Covid-19 on death certificates, 150,116 deaths were recorded by 19 March. However, this measure is less up to date than the government count of fatalities within 28 days of a positive test. The Guardian reported on Saturday that the 150,000 milestone had been passed based on a different methodology.