The UK is enjoying real success with its COVID-19 vaccine coverage. Around 85% of adults (44.8 million people) have received one vaccine dose and 63% (33 million people) both doses, with around 160,000 doses a day still being administered.
Vaccination with two doses helps prevent infection, and in those that do still get infected, lessens the impact of the virus by reducing disease severity, transmission of infection and death.
Even so, plans to give people a third shot have been unveiled by the UK's Joint Committee on Vaccination and Immunization (JCVI). The two main arguments to support giving a third dose are that the effectiveness of the first two jabs falls over time, and that there's a need to take new vaccines to deal with viral variants, such as the delta variant. But what does the evidence say?
Several studies have investigated the durability of immunity to COVID-19, and their results are encouraging. Researchers have focused on specialized white blood cells called lymphocytes. Lymphocytes come in two main varieties: B cells, which make antibodies, and T cells, which can help the B-cell response or directly kill the COVID-19 virus.
Antibodies play a critical role in stopping viruses entering the body's cells, which is what the virus needs to do to replicate. You can readily measure someone's antibody levels in a blood sample, but the data on what a typical person's antibody levels are following vaccination or infection with COVID-19 has been variable.
Vaccination with two doses helps prevent infection, and in those that do still get infected, lessens the impact of the virus by reducing disease severity, transmission of infection and death.
Even so, plans to give people a third shot have been unveiled by the UK's Joint Committee on Vaccination and Immunization (JCVI). The two main arguments to support giving a third dose are that the effectiveness of the first two jabs falls over time, and that there's a need to take new vaccines to deal with viral variants, such as the delta variant. But what does the evidence say?
Several studies have investigated the durability of immunity to COVID-19, and their results are encouraging. Researchers have focused on specialized white blood cells called lymphocytes. Lymphocytes come in two main varieties: B cells, which make antibodies, and T cells, which can help the B-cell response or directly kill the COVID-19 virus.
Antibodies play a critical role in stopping viruses entering the body's cells, which is what the virus needs to do to replicate. You can readily measure someone's antibody levels in a blood sample, but the data on what a typical person's antibody levels are following vaccination or infection with COVID-19 has been variable.
Read more:
https://medicalxpress.com/news/2021-07-covid-vaccine-boosters-dose.html
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου