Everything you need to know about COVID-19 vaccines.

COVID-19, the potentially fatal respiratory illness first detected in December 2019, has spread across the globe,forcing the cancellation of major events, postponing sports seasons and sending many into self-imposed quarantine. As health authorities and governments attempt to slow the spread, researchers are focusing their attention on the coronavirus that causes the disease: SARS-CoV-2.

Since it was first discovered as the causative agent of the new disease, scientists have been racing to get a better understanding of the virus' genetic makeup, how it infects cells and how to effectively treat it. Currently there's no cure and medical specialists can only treat the symptoms of the disease. However, the long-term strategy to combat COVID-19, which has spread to every continent on Earth besides Antarctica, will be to develop a vaccine.

Developing new vaccines takes time and they must be rigorously tested and confirmed safe via clinical trials before they can be routinely used in humans. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the US, has commonly stated a vaccine is at least a year to 18 months away. Experts agree there's a ways to go yet.

Vaccines are incredibly important in the fight against disease. We've been able to keep a handful of viral diseases at bay for decades because of vaccine development. Even so, there exists confusion and unease about their usefulness. This guide explains what vaccines are, why they are so important and how scientists will use them in the fight against the coronavirus. As more candidates appear and are tested, we'll add them to this list, so bookmark this page and check back for the latest updates.

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A vaccine is a type of treatment aimed at stimulating the body's immune system to fight against infectious pathogens, like bacteria and viruses. They are,according to the World Health Organization, "one of the most effective ways to prevent diseases."

The human body is particularly resilient to disease, having evolved a natural defense system against nasty disease-causing microorganisms like bacteria and viruses. The defense system -- our immune system -- is composed of different types of white blood cells that can detect and destroy foreign invaders. Some gobble up bacteria, some produce antibodies which can tell the body what to destroy and take out the germs and other cells memorize what the invaders look like, so the body can respond quickly if they invade again.

Vaccines are a really clever fake-out. They make the body think it's infected so it stimulates this immune response. For instance, the measles vaccine tricks the body into thinking it has measles. When you are vaccinated for measles, your body generates a record of the measles virus. If you come into contact with it in the future, the body's immune system is primed and ready to beat it back before you can get sick.

The very first vaccine was developed by a scientist named Edward Jenner in the late 18th century. In a famous experiment, Jenner scraped pus from a milkmaid with cowpox -- a type of virus that causes disease mostly in cows and is very similar to the smallpox virus -- and introduced the pus into a young boy. The young boy became a little ill and had a mild case of cowpox. Later, Jenner inoculated the boy with smallpox, but he didn't get sick. Jenner's first injection of cowpox pus trained the boy's body to recognize the cowpox virus and, because its so similar to smallpox, the young man was able to fight it off and not get sick.

Vaccines have come an incredibly long way since 1796 though. Scientists certainly don't inject pus from patients into other patients and vaccines must abide by strict safety regulations, multiple rounds of clinical testing and strong governmental guidelines before they can be adopted for widespread use.

Vaccines contain a handful of different ingredients depending on their type and how they aim to generate an immune response. However, there's some commonality between them all.

The most important ingredient is the antigen. This is the part of the vaccine the body can recognize as foreign. Depending on the type of vaccine, an antigen could be molecules from viruses like a strand of DNA or a protein. It could instead be weakened versions of live viruses. For instance, the measles vaccine contains a weakened version of the measles virus. When a patient receives the measles vaccine, their immune system recognizes a protein present on the measles virus and learns to fight it off.

A second important ingredient is the adjuvant. An adjuvant works to amplify the immune response to an antigen. Whether a vaccine contains an adjuvant depends on the type of vaccine it is.

Some vaccines used to be stored in vials that could be used multiple times and, as such, contained preservatives that ensured they would be able to sit on a shelf without growing other nasty bacteria inside them. One such preservative is thimerosal which has garnered a lot of attention in recent times because it contains trace amounts of the easily-cleared ethylmercury. Its inclusion in vaccines has not been shown to cause harm, according to the CDC. In places like Australia, single-use vials are now common and thus preservatives such as thimerosal are no longer necessary in most vaccines.

In developing a vaccine for SARS-CoV-2, scientists need to find a viable antigen that will stimulate the body's immune system into defending against infection.

The pathogen at the center of the outbreak, SARS-CoV-2, belongs to the family of viruses known ascoronaviruses. This family is so named because, under a microscope, they appear with crown-like projections on their surface.

In developing a vaccine that targets SARS-CoV-2, scientists are looking at these projections intensely. The projections enable the virus to enter human cells where it can replicate and make copies of itself. Known as "spike proteins" or "S" proteins, researchers have been able to map the projections in 3Dand research suggests they could be a viable antigen in any coronavirus vaccine.

That's because the S protein is prevalent in coronaviruses we've battled in the past -- including the one that caused the SARS outbreak in China in 2002-2003. This has given researchers a head start on building vaccines against part of the S protein and, using animal models, have demonstrated they can generate an immune response.

There are many other companies across the world working on a SARS-CoV-2 vaccine, developing different ways to stimulate the immune system. Some of the most talked about approaches are those using a relatively novel type of vaccine known as a "nucleic acid vaccine." These vaccines are essentially programmable, containing a small piece of genetic code to act as the antigen.

Biotech companies like Moderna have been able to generate new vaccine designs against SARS-CoV-2 rapidly by taking a piece of the genetic code for the S protein and fusing it with fatty nanoparticles that can be injected into the body. Imperial College London is designing a similar vaccine using coronavirus RNA -- its genetic code. Pennsylvania biotech company Inovio is generating strands of DNA it hopes will stimulate an immune response. Although these kinds of vaccines can be created quickly, none have been brought to market yet.

Johnson & Johnson and French pharmaceutical giant Sanofi are both working with the US Biomedical Advanced Research and Development Authority to develop vaccines of their own. Sanofi's plan is to mix coronavirus DNA with genetic material from a harmless virus, whereas Johnson & Johnson will attempt to deactivate SARS-CoV-2, essentially switching off its ability to cause illness while ensuring it still stimulates the immune system.

Some research organizations, such as Boston Children's Hospital, are examining different kinds of adjuvants that will help amplify the immune response. This approach, according to the Harvard Gazette, will be targeted more towards the elderly, who don't respond as effectively when vaccinated. It's hoped that by studying adjuvants to boost a vaccine, the elderly will be able to be vaccinated with a mix of ingredients that can supercharge their immunity.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in the US, posits that a vaccine is at least a year and a half away, even though we're likely to see human trials start within the next month or two. This, according to a 60 Minutes interview with Fauci in March, is a fast turnaround.

"The good news is we did it more quickly than we've ever done it," Fauci told 60 Minutes in March. "The sobering news is that it's not ready for primetime, for what we're going through now."

Why does vaccine production take so long? There's a ton of steps involved and a lot of regulatory hurdles to jump through.

"For any medicine to be sold it needs to go through the standard process of clinical trials including phase 1 [to] 3 trials," says Bruce Thompson, dean of health at Swinburne University in Australia. "We need to ensure that the medicine is safe, will not do harm, and know how effective it is."

Scientists can't assume their vaccine design will just work -- they have to test, test and test again. They have to recruit thousands of people to ensure the safety of a vaccine and how useful it will be. The process can be broken down into six phases:

Traditionally then, it could take a decade or more for a new vaccine to go from design to approval. In addition, once the regulatory processes have concluded a vaccine is safe, the drug companies have to send production into overdrive, so they can manufacture enough of the vaccine to increase immunity in the wider population.

With SARS-CoV-2, the process is being expedited in some instances. As STATnews reports, the vaccine in development by Moderna has moved from design straight into Phase I clinical trials of it mRNA vaccine, skipping tests in animal models. Those tests will take place at Seattle's Kaiser Permanente Washington Health Instituteand patients are now being enrolled.

Until that time though, health workers, doctors and medical specialists must rely on current treatment options.

The best way to prevent illness is avoiding exposure. Those tips are below.

First: Antibiotics, medicine designed to fight bacteria, won't work on SARS-CoV-2, a virus. If you're infected, you will be asked to self-isolate, to prevent further spread of the disease, for 14 days. If symptoms escalate and you experience a shortness of breath, high fever and lethargy, you should seek medical care.

Treating cases of COVID-19 in the hospital is based on managing patient symptoms in the most appropriate way. For patients with severe disease adversely affecting the lungs, doctors place a tube into a patient's airway so that they can be connected to ventilators -- machines which help control breathing.

There are no specific treatments for COVID-19 as yet, though a number are in the works including experimental antivirals, which can attack the virus, and existing drugs targeted at other viruses like HIV which have shown some promise in treating COVID-19.

Remdesivir

Remdesivir, an experimental antiviral made by biotech firm Gilead Sciences, has garnered a lion's share of the limelight. The drug has been used in the US, China and Italy, but only on a "compassionate basis" -- essentially, this drug has not received approval but can be used outside of a clinical trial on critically ill patients. Remdesivir is not specifically designed to destroy SARS-CoV-2. Instead, it works by knocking out a specific piece of machinery in the virus, known as "RNA polymerase," which many viruses use to replicate. It has been shown as effective in human cells and mouse models in the past.

It's effectiveness is still being debated and much more rigorous study will be needed before this becomes a general treatment for SARS-CoV-2, if it does at all.

Other treatment options

A HIV medicine, Kaletra/Aluvia, has been used in China to treat COVID-19. According to a release by AbbVie, an Illinois-based pharmaceutical company, the treatment was provided as an experimental option for Chinese patients during "the early days" of fighting the virus. The company suggests it is collaborating with global health authorities including the CDC and WHO.

A drug that has been used to treat malaria for around 70 years, chloroquine, has been floated as a potential candidate. It appears to be able to block viruses from binding to human cells and getting inside them to replicate. It also stimulates the immune system. A letter to the editor in journal Nature on Feb. 4 showed chloroquine was effective in combating SARS-CoV-2. Another Chinese study emanating from Guangdong reports chloroquine improved patient outcomesand "might improve the success rate of treatment" and "shorten hospital stay."

It is not a good idea to rely on a vaccine to stop the spread of coronavirus because they are many months away. The best way to stop the spread, right now, is to continue practicing good personal hygiene and to limit interactions with others. "The best thing to do is the simple things like hand washing and hand sanitizing," notes Thompson.

This outbreak is unprecedented and changing behaviors is absolutely critical to stopping the spread.

There are a huge number of resources available from the WHO on protecting yourself against infection. It's clear the virus can spread from person-to-person and transmission in communities has occurred across the world. Protection boils down to a few key things:

For much more information, you can head to CNET's guide

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Coronavirus vaccines and treatment: Everything you need to know - CNET