Thought of the Day - October 8 2021 - Delta Spreaders

Studies to this point have been mixed concerning whether there is a difference in transmission levels between those vaccinated and unvaccinated if infected with the Delta strain. Studies have found that people infected with Delta have roughly the same levels of viral genetic materials in their noses regardless of whether they’d previously been vaccinated, suggesting that vaccinated and unvaccinated people might be equally infectious. But studies also suggest that vaccinated people are less likely to spread the virus if they subsequently catch Delta: as their levels of nasal virus drop faster than do those of unvaccinated infected people.

The first major study, involving tracing the fate of hundreds of thousands, looks directly at how well vaccines prevent the spread of the Delta variant of SARS-CoV-2 brings good news and bad. The UK study shows that people who become infected with the Delta variant are less likely to pass the virus to their close contacts if they have already had a COVID-19 vaccine than if they haven’t. But that the vaccine’s beneficial effect in Delta transmission waned to almost negligible levels over time.

In people infected two weeks after receiving the AstraZeneca vaccine, the chance that a close contact would test positive was 15% lower than exposure to an unvaccinated carrier, but three months later, that chance was on par with the likelihood that an unvaccinated person will spread the virus.

Pfizer had a slightly higher initial prevention figure, closer to 20%, but this also disappears over time.

Of course, this real-world study implicitly incorporates some social aspects. With markedly less symptoms, a vaccinated person is more likely to socialize. Moreover, as many vaccinated people naively believe they cannot spread the virus they are unlikely to quarantine and thus act with impunity. Why do people believe they do not transmit Delta you may ask? It is purposely vague statements such as the one our own Bonnie Henry made back in September “Vaccinations have been proven very, very successful at helping us stem the virus’s transmission… ”. These are interpreted as saying vaccines stop transmission - this has no scientific basis.

In short, vaccines have proved very successful in decreasing the likelihood of severe infection but as far as transmission goes, with vaccination, once infected the reduction in the real-world risk of transmission is marginal at best.

Cheers

Cliff

P.S. FYI - Here are this week's top-ten countries across the world in terms of deaths per capita. Notice only Bulgaria is not necessarily a haven for the rich-and-vaccinated tourist.

I say the proof of this pudding is in the eating. You can rest assured that the vast majority of the tourists eating pudding in these holiday destinations are vaccinated and most of these are oblivious to the fact they are spreading the disease in these ill-equipped locales.