Vaccinated “No Less Infectious” Than Unvaccinated, CDC Study Finds

A pre-print study out this week from the U.S. Government’s Covid Response Team at the Centers for Disease Control and Prevention (CDC) has found vaccinated people to be “no less infectious” than unvaccinated people.

The study tested inmates in a federal prison with high vaccination rates daily during a SARS-CoV-2 Delta variant outbreak.

The study was very thorough. Inmates who tested positive for SARS-CoV-2 were, where willing, PCR-tested for 10 consecutive days and reported symptoms via a questionnaire. The researchers performed whole genome sequencing and viral culture analysis on a high proportion of the 978 specimens collected, allowing them to assess the duration of PCR positivity and viral culture positivity.

There were 95 participants in total, of whom 78 (82%) were double vaccinated and 17 (18%) were not double vaccinated (two having received one dose and 15 having received none). No significant differences were found between double vaccinated and not double vaccinated either in duration of PCR positivity (13 days each) or in duration of culture positivity (five days each).

The authors conclude that “clinicians and public health practitioners should consider vaccinated persons who become infected with SARS-CoV-2 to be no less infectious than unvaccinated persons”.

This is in line with the findings of Public Health England and others.

While this sounds like more good news for countering vaccine passports, vaccine mandates and all other vaccine-based coercion and discrimination, it may be less good news for ending general restrictions and interventions. The authors state: “These findings are critically important, especially in congregate settings where viral transmission can lead to large outbreaks.” Which suggests they think the lack of efficacy against transmission is a reason to intervene more generally to prevent “large outbreaks” in “congregate settings”. It could be a long winter.