Protection against Govit-19 increases after the third vaccine dose

At the end of October, the government announced that everyone over the age of 16 would be given a third dose, not six months before the second dose. Booster doses are given by Moderna’s vaccine Spikevax or Pfizer / Biontech’s Comirnaty. Both are so-called mrna vaccines and are very similar to each other.

According to the Medicines Agency, data from clinical trials show that on average you will get a higher antibody response after the third dose compared to the second dose. After the second dose of Caminrati, the titer (antibody concentration measurement) averaged 754 and the third 2,476, according to Pfizer / Biotech data.

However, there is no limit value to the effective protective effect.

The Swedish Institute of Public Health insists A third dose is given to maintain safety after the first and second injections. Even if one sees a rapid rise in antibody levels, the statistics are difficult to estimate.

– We do not know if there is a turning point where you can say “you are no longer safe below that level”, says state epidemiologist Anders Technell.

However, the experience of the UK and Israel shows that the protective effect on the population level increases very rapidly – in just a few weeks – based on how many people test positive for the disease, he says.

– Antibodies are not really interesting, that is the protection we are looking for. The point is that the booster dose was given before you lost protection.

In September, Israeli data showed that the third dose of the Pfizer / Biotech vaccine “restored” 95 percent of the protection against the disease six months after the second dose – comparable to the level of protection after the second dose. Between July 1 and August 30, data were collected when the delta variant was thriving in the country. CNBC News.

That same month, a study was published New England Journal of Medicine People over the age of 60 who received a third dose were less likely to have a positive test for the virus or become seriously ill than those who received only two injections. There were more than 1.1 million people in the study.

When vaccinated against Govit-19 The immune system is stimulated to produce antibodies to the spike protein of the SARS-Cove-2 virus, which it uses to attach to the virus cells.

After the first dose, it takes three to four weeks for the immune system to develop proper antibody levels, after the second the levels increase within one to two weeks and after the third it goes even faster. Farshit Jalalwant, a medical microbiology assistant researcher at the University of Lund, says that when activated by a vaccine or virus, the immune system’s memory cells increase in production after each dose.

– After the third dose, you have memory cells from the first and second dose. This makes the response even faster and the levels rise. But there is variation between different individuals, he says, adding that some may receive antibodies after three days and others after seven days.

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