Covid vaccine update: Tracking progress against coronavirus

The first vaccine to be cleared by U.S. regulators was developed by pharmaceutical giant Pfizer and its German partner BioNTech. BioNTech began working on a vaccine in January, and the companies began working together in March, broadening a joint effort to use the same technology to develop an influenza vaccine. In November, companies reported that the vaccine was more than 90 percent effective in late-stage trials and were granted emergency use authorization on Dec. 11.

These steps are now overlapping in the race to find a vaccine for a global disease that has killed hundreds of thousands of people. Human testing began in some cases before animal studies were finished. As companies launch small Phase 1 trials intended to establish the correct dose, they already are planning the Phase 3 trials that evaluate whether the vaccines are effective and safe.

[What you need to know about the Moderna and Pfizer coronavirus vaccines]

No steps are being skipped, top government officials have repeatedly promised, and vaccines will not be considered for approval in the United States until after a large, Phase 3 trial. The Food and Drug Administration, which has the ultimate say on whether a vaccine has been proved safe and effective, says a vaccine for covid-19, the disease caused by the coronavirus, will need to prevent disease or decrease symptoms in at least 50 percent of those who receive it. The effectiveness of the flu vaccine ranges from 40 to 60 percent, according to the Centers for Disease Control and Prevention.

Other countries may use different standards or authorize vaccines without waiting for proof they are safe and effective. Russia announced it would begin using its vaccine in people at high risk for the virus in August, before starting its Phase 3 trial. China has authorized a vaccine for use in members of the military.

Unprecedented speed

Researchers in the United States set an audacious goal in January to develop a coronavirus vaccine within 12 to 18 months. The vaccine created by Pfizer and BioNTech is the fastest ever developed and authorized in the United States. The mumps vaccine was previously considered to be the fastest to move, in four years, from scientific concept to approval in 1967. The quest for an HIV vaccine continues, 36 years and counting.

Pfizer invested $2 billion of its own money into the vaccine and then struck a $1.95 billion contract with the U.S. government to provide 100 million doses, contingent on the vaccine being effective. Other leading candidates for a vaccine are also moving fast, fueled by government investments that erase the financial risks of developing a vaccine that may not work. Through Operation Warp Speed, the U.S. government has invested nearly $11 billion to speed up development and jump-start manufacturing before research is finished.

Coronavirus vaccines are moving much faster, partly because governments are taking on the financial risk of developing a vaccine that may not work. Through Operation Warp Speed, the U.S. government has invested about $9.5 billion to speed up development and jump-start manufacturing before research is finished.

[The cold rush: Pfizer’s covid vaccine jump-starts race for special freezers]

New technologies

Advancements in science and technology have given researchers new tools to try against the coronavirus. Scientists can deliver genetic material into the body’s cells, turning them into vaccine factories and skipping time-consuming steps such as manufacturing viral proteins or growing the whole virus in chicken eggs.

The Pfizer is the first vaccine using messenger RNA technology ever cleared for human use outside of clinical trials. It is different from more traditional vaccines, which often use a weakened or dead version of a virus, or a laboratory-generated protein.

The core of the coronavirus SARS-CoV-2 is a single strip of ribonucleic acid (RNA) surrounded by a protein shell. The virus is named for the iconic spikes that project from its center like a crown, or “corona” in Latin. These spike proteins aren’t just decoration. They are critical for the virus to get inside cells and make copies of itself.

Vaccines work by teaching the body’s immune system to recognize and block viruses. Each category of vaccine technology works under this basic principle. Vaccines aim to activate the immune system’s T-helper cells, which are responsible for detecting the presence of a virus. They instruct B-cells to create antibodies that block the virus from being able to replicate and T-killer cells to destroy infected cells. Some vaccines may activate only part of this immune response.

Here is a look at how different vaccine technologies being developed around the world would ideally elicit an immune response to prevent SARS-CoV-2 in humans. Each vaccine may vary somewhat in how it works, but each would generally follow these steps.

Vaccines using nucleic acid (DNA and RNA)

DNA vaccines contain genetic material that carries the blueprint for the spike protein. To get the DNA into cells, researchers use an electrical pulse to disrupt the cell membrane. Once inside, the DNA is used as a template to create spike protein.

RNA vaccines contain a strip of genetic material within a fat bubble. Once inside the cell, the RNA generates a protein found on the surface of the virus. The immune system, presented with the protein, learns to recognize the virus.

These vaccines have the advantage of speed — they can be quickly designed and manufactured. But they have never been approved for use outside of medical research and will likely require two doses.