Biomedical sciences lab equipment

University of Hull virologist answers biggest COVID-19 questions on vaccines and testing

Our virologist and lecturer Dr Cheryl Walter recently answered some of the biggest questions surrounding COVID-19. 

Dr Walter, a lecturer in microbiology at the University, shared her 15+ years of experience working with viruses and virus-host systems in a Q&A with the Hull Daily Mail. 

She answered questions surrounding the creation of a vaccine for COVID-19, the human trials process and how we can slow the spread of viruses such as this.

Read her full Q&A below: 

Dr Cheryl Walter

Dr Cheryl Walter, a lecturer in microbiology at the University of Hull

Why has Covid-19 been so devastating and widespread compared with other viruses?

We don’t really know. Health organisations have been predicting a pandemic was due, but perhaps what makes this virus so dangerous is a) it’s more infectious than influenza virus, which many predicted might be the next pandemic and b) infections have a higher mortality rate.

Is a vaccine the best way of tackling the Covid-19 pandemic? 

Absolutely! Prevention is always better than cure. We can protect virtually everyone in the whole community long-term, with vaccination.

How do you go about creating a vaccine?

There are a few different ways of making a vaccine. What is the quickest and most universally applicable approach, is to make a subunit vaccine. A subunit vaccine contains only a small stretch of viral protein in it to generate an immune response that protects you from a real infection.  

Importantly, this small stretch of protein is chosen because your immune system recognizes it as ‘foreign’ and makes those protective antibodies. Secondly, this little piece of protein is artificially made, making this an easy to mass produce and entirely safe vaccine.

These vaccines can be given to virtually everyone and are completely safe. A very small number of people with certain allergies of pre-existing conditions might not be able to have the vaccine but, this is always carefully checked before administering it.

There are human trials going on now. What happens next?

There are plenty of important trials going on right now, exploring lots of treatment options. We are already starting to get valuable information from some of them that are completed (such as the remdesivir trial).

This information is being communicated on a global scale and then carefully analysed as quickly and safely as possible, so that clinicians have even more treatment options for Covid-19 patients that are seriously ill in hospital.

How long can it take to create a vaccine that is safe to use on people? 

Vaccines take years to develop. This situation right now means that a huge, multinational effort is underway to develop a safe and effective vaccine, but this still needs to be tested in clinical trials before it can be approved and rolled out to the public.

Some vaccines are very difficult to make, while others can be based on existing technologies. Scientists have long been working on ways to make the process more adaptable so that, in the case of subunit vaccines, a scaffold process is already in place and all that is needed is to successfully identify and make those small, antigenic proteins. The cherry on top, so to speak.

How many people would need to be vaccinated to prevent the virus spreading?

This is something we still need to work out.  For very infectious illnesses, like Measles, approximately 95% of a community need to be immunized to almost completely stop it from spreading. SARS-COV 2 is less infectious than Measles virus, but a community still needs a high percentage of immune people, to stop an infectious disease from spreading. 

Who would be the first to be vaccinated? 

The elderly, people with pre-existing conditions, pregnant women and children. In what order this group would be prioritized, I am not sure. 

What is contact tracing? 

Imagine you had invisible ink on your hands and went about a normal day commuting to and from work before you noticed. Contact tracing involves finding out who would have been close enough to you for that whole day you had the ink on your hands.   

That ink is really sticky and transfers to other people close to you off surfaces. Although this is a completely harmless example, you’d want to find out who also now had the invisible ink on their hands and then who did they come into contact with. 

Contact tracing is difficult and would be used in our current situation, to notify individuals who’d come into contact with someone who had tested positive for Covid-19 and asking these traced contacts to self-isolate for precautionary measures. By doing this, you are potentially limiting that spread of a virus from one person to around another three other people and so on, as is the case of SARS-COV 2.

How does contact tracing work? 

There are a few ways of doing this. The first is to interview the person with the ink of the hands and ask them to list who they got close to during a certain period. This relies on the person remembering everyone they came close to, which can be difficult and also knowing who these people are so they can be contacted.  

Another way of doing it, is to have an app on your phone that collects data on who you came close to over a certain period of time. If someone tests positive, that chain of contacts can be quickly accessed and these people contacted using the same app. Again, this has the drawback on potentially involving tracking the movements of individuals, which needs to be carefully managed, and also that these people would need to have their phone on their person to register these close contacts. 

This might not be a viable option for people who don’t have a smartphone or for people that don’t have it on them all day. 

Is it an effective way of trying to control the spread of a virus such as Covid-19?

Yes, I think so. As the number of new infections decrease and with social distancing measures still in place, now is a good time to consider implementing contact tracing. The number of people we are in contact with is already reduced, making it easier to remember and trace these individuals.

By suggesting the traced individuals then self-isolate for the recommended period of time will further reduce new infections in a targeted way, perhaps allowing for a gradual relaxing of the blanket social distancing measures that are currently in place.  It is also a great opportunity to study transmission in the population and to learn from it.

What other ways are there to tackle the spread of a virus such as Covid-19?

Washing hands, continue to adhering to social distancing policies. For those exhibiting symptoms, to catch coughs in a handkerchief or crook of your elbow but even more importantly, to self-isolate for the stipulated time if you suspect you have Covid-19. 

Masks might be useful, especially if you are ill as they help to catch many of the droplets that you expel when you cough, sneeze and talk. 

Media Enquiries

Please contact the Press Office on