How does vaccination prevent infection

People who are fully vaccinated against COVID are far less likely to become infected and infect others, even with the arrival of the delta and delta plus variants. As cases rise sharply in the UK, however, fears are spreading over how effective vaccination is against the virus. But what does the research suggest - and what do experts say about the efficacy of the COVID vaccines? The COVID vaccination booster programme is well underway in the UK, with an increasing number of eligible people being offered their third jab.

According to NHS England , more than five million people have had a third vaccine since the vaccination programme began administering them last month. Multiple studies suggest being vaccinated significantly reduces the chance of testing positive for COVID Higher protection still was found among those who had experienced a past infection followed by two vaccines.

Two doses of either the Pfizer or the AstraZeneca vaccine provided a similar level of protection to prior natural infection when the Delta variant was dominant, the research found. However, it also showed that vaccines were slightly less effective against the Delta variant compared with the Alpha variant. Earlier this year, a separate study led by Imperial College London found that double vaccinated people were three times less likely than unvaccinated people to test positive for coronavirus.

This is only slightly lower than with the Alpha variant. Vaccination wiped out smallpox. In there were 10 to 15 million cases of smallpox worldwide. That year WHO began a campaign to vaccinate people all over the world.

The last natural case of smallpox was recorded in Africa in Vaccines and vaccination Vaccinations give protection against specific diseases, but the level of protection in a population depends on the proportion of people vaccinated. The first kind of white blood cell makes antibodies which cause the pathogens to clump together. The second type of white blood cell second destroys the pathogen by engulfing and digesting it.

This process is also called phagocytosis. Choose your subscription. Trial Try full digital access and see why over 1 million readers subscribe to the FT. For 4 weeks receive unlimited Premium digital access to the FT's trusted, award-winning business news.

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