October 28, 2021

Study on household transmission of SARS-CoV-2, looking at variant type and vaccination status

Scientists have carried out a study on household transmission of SARS-CoV-2, and they look at whether viral load and likelihood of transmission of SARS-CoV-2 within households differed depending on the variant of the virus and the vaccination status of the case or the contact.

This study has been published in the Lancet Infectious Diseases.

Journalists dialled in to this briefing to hear the scientists who conducted the study discuss aspects such as:

– what does this study tell us about household transmission?

– how common were ‘breakthrough infections’ in the household?

– how often did fully vaccinated contacts contract the virus?

– were there differences depending on whether it was the Delta, Alpha or Wuhan variant?

– was viral load in infected people different in those vaccinated compared to those unvaccinated?

– was there a difference in likelihood of breakthrough infections depending on time since vaccination?

Speakers included:

Dr Anika Singanayagam, Honorary Clinical Research Fellow, Department of Infectious Disease, Imperial College London

Prof Maria Zambon, Head of Influenza and Respiratory Virology at UKHSA, and Co-Director of NIHR Respiratory Health Protection Unit at Imperial College London

Prof Neil Ferguson, Director of the MRC Centre for Global Infectious Disease Analysis, Imperial College London

Prof Ajit Lalvani, Chair of Infectious Diseases, and Director of the NIHR Health Protection Research Unit in Respiratory Infections, Imperial College London

This Briefing was accompanied by an SMC Roundup of Comments.