With the emergence of SARS-CoV-2 variants worldwide, the pandemic’s spread is accelerating.
In a new study from Université de Montréal, researchers found that those who received the Pfizer BioNTech or AstraZeneca vaccine had antibody levels that were much higher than infected individuals.
These antibodies were also effective against the Delta variant, which wasn’t present in Quebec when the samples were collected in 2020.
Moreover, older people produced more antibodies than adults under 50 years of age.
In the study, 32 non-hospitalized COVID-19 positive Canadian adults were recruited 14 to 21 days after being diagnosed through PCR testing. This was in 2020, before the Beta, Delta and Gamma variants emerged.
The team found everyone who had been infected produced antibodies, but older people produced more than adults under 50 years of age.
In addition, antibodies were still present in their bloodstream 16 weeks after their diagnosis.
Antibodies produced after an infection by the original, “native” strain of the virus also reacted to SARS-CoV-2 variants that emerged in subsequent waves, namely Beta (South Africa), Delta (India) and Gamma (Brazil), but to a lesser extent: a reduction of 30 to 50%.
The team says when someone who has had a mild case of COVID is vaccinated, the antibody level in their blood doubles compared to an unvaccinated person who has been infected by the virus. Their antibodies are also better able to prevent spike-ACE-2 interaction.
They also found samples from an individual younger than 49 whose infection didn’t produce antibodies inhibiting spike-ACE-2 interaction, unlike vaccination.
This suggests that vaccination increases protection against the Delta variant among people previously infected by the native strain.
The scientists believe more research should be conducted to determine the best combination for maintaining the most effective level of antibodies reactive to all variants of the virus.
If you care about COVID, please read studies about why COVID-19 vaccines linked to blood clotting and findings of many COVID-19 survivors have a higher risk of death, serious illness.
For more information about COVID and your health, please see recent studies about this diet may help reduce inflammation in COVID-19 and results showing that people should receive COVID-19 vaccine before surgery.
The study is published in Scientific Reports. One author of the study is Joelle Pelletier.
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