One of the main concerns to live with the delta variant is that people vaccinated, if they are infected, have the same ability to transmit the virus than those not vaccinated.
Even with the same viral load, vaccines are less infectious, it is a hypothesis that was by measuring the viral loads of the individuals infected with Delta, which turned out to be very high.
This dynamic has often been used as an argument for anti vaccines, but has been refuted over time by case numbers.
Relative scientific studies, however, were still scarce. Now an important study of the University of Oxford has come out.
The investigation, dated September 29 and not yet reviewed, says that people vaccinated are less infectious, even with Delta.
In addition, it shows that children appear to be less infectious and less susceptible, just as they did it with the other variants.
The data was obtained from a SARS-COV-2 contact study infected by the ‘index cases’ (the first infected of an outbreak) using United Kingdom swab data between January 2, 2021 and August 2,
2021.
The “second infections” occurred mainly by contact within families (70%), but also after home visits (10%), events or activities (10%) and at work or school (10%).
The results showed that two doses of Pfizer or AstraZeneca in cases of alpha variant reduced the positivity of the PCR in the contacts.
Even with the Delta variant, vaccines attenuated associated infections: two doses of Pfizer reduced the transmission rather than with AstraZeneca.
Protection against infections has decreased over time.
After the second vaccination, Delta returned to levels similar to those not vaccinated in 12 weeks with the AstraZeneca vaccine, and Pfizer saw a substantial decrease in protection after that time, but not so drastic.
Infections of the delta variant had higher viral loads than those of alpha in symptomatic and asymptomatic infections, regardless of the vaccination state. Viral load of vaccinates and not vaccinated was similar.
This did not lead to the same probability of infection: most of the protective effect of vaccines remained, that is, the study showed that other factors are important to reduce the transmission associated with the vaccine.
For example, write the authors of the article, “Vaccination may provide a faster removal of viable infectious virions, leaving behind ineffective and damaged virions that still contain detectable RNA by PCR.
The measurement of the viral load, therefore, it takes up how infectious the people vaccinated are.
This suggests more than anything a greater infectivity of the virus itself, not only as a factor in the dynamics of the viral load.
Vaccinated people are not as contagious as people not vaccinated infected with delta, even with the same viral load.
