Mapping patterns of viral load emission in exhaled breath over the course of acute respiratory virus infections

Background Respiratory virus infections can cause significant problems for infected patients, the economy and the NHS. The most profound example of this is the COVID-19 pandemic, but seasonal flu and other viruses also exist. In older frail patients, such infections can be fatal. The diagnosis of respiratory virus infections is by a swab in the back of the throat and nose (nasopharyngeal swab). However, this can be very uncomfortable - and although it can help a doctor diagnose whether someone has a respiratory virus infection, it doesn't necessarily tell us whether that person is contagious to others. This is likely because most people who get exposed to an infected person are not exposed to the virus in their throat, but by the virus that they breathe out. In fact, many patients who are positive for SARS-CoV-2 on the nasopharyngeal swab are not contagious to others if they are already several days into their illness. Study aims I have supported the development of a method to sample virus that is breathed out by infected patients, by using harmless strips that are placed on the inside of routinely used duckbilled-shaped facemasks. These strips are able to quantify the amount of virus that someone breathes out over time. We have recently shown that this mask based sampling system is able to detect SARS-CoV-2 virus in infected patients. The aim of this PhD fellowship is see whether the amount of virus detected time on the facemask is different to that detected by the nasopharyngeal swab. Ultimately, the mask could be a more accurate marker of individual contagiousness than the nasopharyngeal swab. If this is the case, it could be of immediate public health benefit, allowing infectious patients to be isolated before they are symptomatic; allowing non-contagious patients to be discharged to a nursing home in a timely fashion without worry of transmission to other residents; as well as allowing non-contagious persons to go to work or travel abroad. Methods There are three work packages (WP) of this fellowship: Work package 1: To systematically review existing methods of sampling the breath for bacteria and viruses Work package 2: To sample 100 study participants and one member of each of their households using the masks with the special strips inside and the nasopharyngeal swabs. Each study participant will provide five masks and swab samples over two weeks. The design of this study will form the basis for future bigger studies and will see if there are any problems with patients wearing the masks; how many patients can we get at different stages of infection; if patients can be followed up successfully; what measures might work well for future, larger studies. Study participants will also fill out a symptom diary, grading their symptoms on a daily basis and a brief questionnaire detailing their basic demographic details (age, sex, ethnicity etc). Work package 3: Use mathematical modelling methods to try and map out quantities of virus throughout the first two weeks of illness based on WP2 data. Patient and public involvement (PPI) PPI has been in place since the study was conceived and will continue throughout the project. I sought the opinion of ten PPI representatives, all of whom thought the work was important and will form a project group that will meet bi-annually to discuss study results. Dissemination of findings Results will be shared with participants and the public through the involvement of PPI representatives; presented at academic conferences and published in high impact journals.