An American study reinforces fears.. Corona vaccinators may need an additional dose

New data indicate that the effectiveness of some vaccines against the emerging coronavirus "Covid-19" may decline within 6 months after receiving them, so what are these vaccines?

What is the percentage of decline?

What is the impact of the Delta Dynasty in this decline?

The answers and more are in this report.

We start in America, where a recent study found that the effectiveness of the coronavirus vaccine in the United States fell by a third once the delta strain became dominant in the country.

A new study published Tuesday by the Centers for Disease Control and Prevention showed that the effectiveness of the vaccine against corona decreased from about 91% to 66% once it became Delta dominant in the United States.

This decrease indicates the highly contagious nature of the delta variant and underscores the importance of vaccination to prevent severe illness, hospitalization, and death, the study authors wrote.

An independent British study concluded last week that the effectiveness of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines against the now-dominant Delta strain weakened within 3 months, as the effectiveness of the Pfizer vaccine decreased from 75% to 61%, and the effectiveness of the AstraZeneca vaccine decreased from 85% to 68%.

Retreat after 6 months

Moving on to Britain, researchers say the protection provided by two doses of the Pfizer-Biontech and Oxford-AstraZeneca vaccines begins to wear off within 6 months, indicating the need for a booster.

An analysis of data collected by the (Zoe Covid) application company concluded that the effectiveness of the Pfizer vaccine decreased from 88% a month after receiving the second dose to 74% after 5 to 6 months.

For AstraZeneca, the efficacy decreased from 77% to 67% after 4 to 5 months.

The study was based on data from more than one million users of the application, and compared the injuries reported by the owners of those who received the vaccine and the injuries among a group that did not receive the vaccine.

The researchers stated that there is a need for more data for younger groups, given that most of the study participants who received the vaccine up to 6 months before, were elderly, as they were among the groups that had priority in vaccination.

Tim Spector, the company's founder and lead researcher in the study, said that under a worst-case scenario, protection could drop to less than 50% for the elderly and medical staff by winter.

 "This highlights the need for some action. We cannot just sit back and see the protection slowly fade away while the infection rate is still high, and the chances of infection are also high," he told BBC television.

For its part, Johnson & Johnson, the pharmaceutical company, announced Wednesday that its data on the Corona virus vaccine showed that it is best for people who received one dose to get a second dose after 6 months.

The company said in a statement that the results of its research on the booster dose showed that it significantly strengthens the immune response.

A booster dose may be a must

All these data may indicate the need to start giving a booster dose of the Corna vaccine, to deal with the decrease in effectiveness over time, and also with the highly contagious Delta strain.

Britain and other European countries plan to start a vaccination campaign with a booster dose against Covid-19 later this year, after the top vaccine advisers said that the vaccination of the elderly and the most vulnerable groups with a third dose may be necessary from September.

French Prime Minister Jean Castix said today, Thursday, that France intends to release booster doses of Covid-19 vaccines in nursing homes from September 12 or 13.

Castex told RTL radio that people over the age of 65 and suffering from any health conditions can also book appointments to receive a booster dose from early September, adding that there should be 6 months between the second and third doses. .

On Tuesday, France's High Health Authority recommended a booster dose of coronavirus vaccines for all people aged 65 or over, and also for those suffering from chronic health conditions that may put them at risk when infected with Covid-19.