Researchers profiled the antibodies generated by vaccination and then examined their neutralizing capacity. In addition to antibodies circulating within the blood, they checked for the presence of antibodies in saliva as a “first line of defense”.

They adapted an assay that measures the antibodies present against SARS-CoV-2 and other coronaviruses in the blood, to include targets from variants of concern and to look specifically at the neutralizing antibodies. They collected samples from 23 vaccinated individuals who had been vaccinated with Pfizer BioNTech vaccine after the first and second doses.

For control groups, the team collected samples from 35 infected blood donors (age 40-78 years, 29% female) 27 infected saliva donors (age 25-58 years, 63% female) and 49 non-infected saliva donors (age 25-38 years, 55% female) and also control samples of blood and saliva sourced commercially from before the pandemic began.

Vaccinated individuals found to have large amounts of antibodies present compared to infected individuals, suggesting that vaccination not only offers protection against becoming infected, but should you become infected, it reduces the possibility of you transmitting it to others.

The number of antibodies produced and protection offered by vaccination increased substantially after the second vaccine dose was given, showing the importance in receiving the second dose.

Researchers examined whether the protection offered against two variants was similar or different to that offered against the “wild-type”.

There was no reduction in neutralizing antibodies against the alpha variant, there was a substantial reduction in neutralizing antibodies against the beta variant. “This shows the importance of constantly updating vaccines to offer maximum protection against different strains of the virus,” explains Dr Schneiderhan-Marra.

Researchers have developed their assays to include more targets from variants of concern, such as delta (India) and gamma (Brazil), along with other variants of interest (eta, iota, zeta, theta, kappa and epsilon), and other interesting strains such as the mink mutation discovered last year.

Dr Schneiderhan-Marra says: “Two further questions remain however with regards to vaccination: firstly, what protection is offered by the current vaccines against the delta and any other variants that arise in the future, and secondly, how long does protection offered by the current vaccines last and will you need a booster shot to not only increase protection generally, but to also offer protection against new variants?”

Further study is looking at how neutralizing antibodies differ between different vaccines, and finally other studies are looking into other variants and their impact on protection.

Source: Medindia