Is herd immunity threatened by delta variation? | Corona virus: Ontario

Prior to its inception, it was estimated that 75% to 80% of the population would need to be vaccinated to achieve the goal.

Due to the delta variation, immunizations of this size may be very limited.

Instead of giving a measured target for immunization, Ontario Health Assistant Medical Officer Dr. Barbara Yaff spoke at a press conference Monday about the progress of the delta variation. It is best to vaccinate everyone twice.

As of Monday, more than 12% of Ontario people had completed their COVID-19 vaccination cycle.

Epidemiologist David Bisman, who sits at the Ontario Scientific Advisory Table on COVID-19, estimates on Twitter that, for a number of reasons, 90% of people become immune when they are vaccinated.

First, the delta variant is more contagious than other strains of the corona virus. The United Kingdom is one of the vaccine champions It was forced to delay its restoration before the impulse of the variant. The country agreed last week 40% more contagious It hit third waves in Ontario, more than the alpha variant that has dominated so far.

Two sizes are more effective against variation than one

Later, people may be affected by delta variation even after receiving the first dose of the COVID-19 vaccine.

Among those with vaccine doses, we find that the spread is even higher. Features of severity are greatly reduced based on mortality and hospitalization, but this does not stop the spread.

Recent assessments by Nathan Stalin, deputy director of the Scientific Advisory Schedule, show effective safety 30 to 40% after the first injection, increasing to 70 to 80% with the second dose.

Now, with only one vaccine, if a second vaccine is not available, we will not be able to achieve herd immunity quickly., Commented Eric Arts, an immunologist at Western University.

Areas of Ontario where delta variability is high Accelerated its distribution Since last week, Ontario has decided to reduce the gap between the administration of two injections, Pfizer, Moderna (28 days) and AstraZeneca (8 weeks).

But, overall, vaccine and physical distance variations also vary, as cases continue to decline, said Dr. Santiago Perez, an epidemiologist at Kingston General Hospital.

This joint immunity, no magic number. Once we get 30-40%, we start to get a little bit of collective protection, He was relaxed.

In collaboration with Stella Dubin