Why do we need a vaccine for COVID-19?

How are vaccines developed? And when will a coronavirus vaccine be available?‍

As COVID-19 continues to sicken and kill thousands of people around the world, politicians, health professionals and the public are wondering how to get out of lockdown and start to return to normal life. But this won’t be simple. 

Without a vaccine against SARS-CoV-2- the coronavirus that causes COVID-19 - there will always be a risk that new outbreaks of the disease will emerge. 

While rigorous testing, contact tracing and quarantine procedures will help to control the spread COVID-19, the only way to significantly reduce the threat is for enough of the population to become immune to the virus so they cannot pass it on. 

For this to work, we need around 60% of the population to be immune to the disease. However, as it stands, estimates suggest that only approximately 2-14% of people could currently be immune to coronavirus infection, although this could be higher in some cities. 

Widespread community immunity (often known as ‘herd immunity’) can be achieved either by many people becoming infected - which is extremely risky and costs thousands of lives - or through vaccination. It’s no surprise that many politicians and scientists see a COVID-19 vaccine as the only safe route back to normality. 

In this post, take a look at how a coronavirus vaccine will help protect us against COVID-19. We review how scientists are developing vaccines against coronavirus so quickly, what progress has been made so far, and how long it will take before a vaccine is ready for widespread use.

‍How do you make a vaccine against coronavirus?‍

Vaccines can be thought of as ‘training programmes’ for the immune system, teaching your immune cells to recognise and destroy invading bacteria and viruses (pathogens) that cause disease. 

Most vaccines contain either a small part of a microbe that causes a disease, or a harmless form of the whole pathogen. When the vaccine is injected into your body, your immune system initiates a response without actually making you ill. So, if you go on to encounter the real disease at a later date, you’re protected because your body already knows what it looks like and how to deal with it.

So far, COVID-19 vaccine development has centered around using one particular part of the coronavirus - the spike proteins on the surface - to generate immunity. 

The SARS-CoV-2 virus responsible for COVID-19 consists of genetic material contained in a membrane littered with spike proteins. The virus binds to and enters cells in your respiratory system using the spikes, then hijacks the cellular machinery to make more copies of itself.

‍How close is a COVID-19 vaccine?‍

Research into vaccines for COVID-19 has progressed very quickly compared to previous immunisations. That’s thanks to both a global research effort backed by governments and public health organisations, but also a result of using new genetic technologies to rapidly identify potential vaccine candidates.

A team of Chinese scientists sequenced the virus’ genetic material and published it on January 12th, kicking off intensive vaccine research and testing all over the world. The first vaccine candidates were ready for pre-clinical testing in animals just weeks later, and a few have already gone into clinical trials in human volunteers. ‍

As of April 8th, there were 115 vaccine candidates in development, each with their own strategy for generating immunity. 

Some rely on injecting the virus spike proteins into the body, or delivering a harmless weakened form of the entire virus. Others use various techniques to deliver genetic material from the virus into your cells, which then make the spike proteins required to generate immunity. ‍

When will the coronavirus vaccine be ready?‍

The most important thing for any coronavirus vaccine is that it is safe and effective. Six vaccine candidates have already entered Phase I clinical trials in humans, which are designed to test if the vaccines are safe and can trigger an immune response, not whether they are effective in preventing the disease. 

Further larger trials must show the vaccine offers adequate protection against COVID-19. Then, once a vaccine is proven to be safe and effective, it must still conquer the challenges related to scaling up, manufacture and distribution to billions of people all over the world.

There is no such thing as a ‘sure thing’ in vaccine development. At the moment, it’s not even clear if people become immune to COVID-19 after contracting the disease, and if they do, how long immunity lasts. 

The fact that there are so many candidates in development increases the chances that one or more of them will succeed. Rather than being a race with only one winner, this is more like a penalty shootout with a hundred shots at the goal.

Even so, timelines for when we might have a vaccine are uncertain, and with good reason: many promising vaccine candidates fail clinical trials. 

Some scientists have suggested a vaccine could optimistically be rolled out to some groups later this year, with others saying it will be mid-2021 at the earliest.

‍Will we be stuck in lockdown until we have a vaccine? ‍

Until a vaccine is widely available, all we can do is monitor the spread of COVID-19 through rigorous monitoring, testing, contact tracing and quarantine or other lockdown restrictions where necessary.‍

Our COVID Symptom Tracker app is a powerful tool for seeing how many people are likely to be infected and where they live, giving policy-makers and healthcare providers the vital data they need to see how well lockdown measures are working and when they might be lifted.‍

And when a vaccine is ready, we can use what we have learned from our app to identify where the vaccine is needed most, who is most at risk, and who should get it first.‍

To sum up:

• Vaccines protect us from disease by giving us immunity without getting sick.
• They usually contain part of a pathogen causing the disease, which trains our immune systems to protect us
• There are more than one hundred coronavirus vaccines in development around the world, with various strategies for generating immunity 
• Some vaccines have reached clinical trials, but have not yet been shown to be safe and effective 
• It is likely to take many months to find one or more effective vaccines against COVID-19
• In the absence of a vaccine, how long we will be in lockdown depends on what other steps we take to control the spread of the disease 
• Symptom tracking is one important way to monitor and contain the spread of COVID-19 and ease lockdown restrictions
  

Find out more:

• Coronavirus: can herd immunity protect us from COVID-19?  – Science Focus
• WHO warns that few have developed antibodies to Covid-19 – The Guardian 
• How Coronavirus Hijacks Your Cells – The New York Times 
• The COVID-19 vaccine development landscape – Nature Reviews Drug Discovery
• Where are we at with developing a vaccine for coronavirus? – The Conversation
• Can You Be Re-Infected After Recovering From Coronavirus? Here's What We Know About COVID-19 Immunity – Time 
• How long will COVID lockdown last?