How much should we trust each other on vaccines?

If one country approves a coronavirus vaccine, should another just trust it and follow suit? Covid-19's rapid global spread pushed labs and manufacturers to develop vaccines quickly. Several are now in use and more are in various stages of development. Early predictions that a vaccine would take 12 to 18 months to arrive seemed optimistic. Hand it to the pharmaceutical companies; they stepped up and delivered.

Now, the greater burden is on regulators to deploy vaccines in their countries. Drug approval processes vary by nation and there isn't a universal one-stop procedure, though various bodies tend to communicate. This means timelines of deployment vary from place to place, often delaying shots going into arms.

At one end of the spectrum South Africa, which bypassed its regulator altogether to hasten vaccinations. At another is Japan, which isn't expected to approve the Moderna Inc. jab until May because of local clinical trial rules. The vaccine has been green-lighted in the U.S. and been in use since mid-December. In Tokyo, Prime Minister Yoshihide Suga has taken the unusual measure of going around his health ministry directly to Pfizer Inc. to speed up the U.S. company's application for approval in Japan. That could mean the country will receive required data this month instead of next and could administer the vaccine Pfizer developed with BioNTech SE by the end of February.

For everyone taking the vaccine sooner or later, a lot rides on trust in the approval process. The U.S. Food and Drug Administration is the oldest of its kind and has developed a deep well of public confidence. So have regulators in other places. Who to trust as experts try keeping up with the way manufacturers have accelerated vaccine development? In the U.K., the Pfizer-BioNTech shot was green-lighted within days, using a rolling review deployed during public health emergencies. The top U.S. infectious diseases expert, Anthony Fauci, initially bemoaned the U.K.'s rapid approval, and later apologized.

Meanwhile, the Covid-19 vaccine from AstraZeneca Plc and the University of Oxford has had its share of approval issues in the U.S. compared with a smoother process in the U.K. A lot more data was requested in the U.S., a process the company's chief executive, Pascal Soriot, said in a November interview with the Wall Street Journal was "nerve-racking in terms of the time that it took."

National authorities are faced with a gargantuan task and risk. The vaccine development process typically takes years to decades, drawing in around a dozen people (plus animals) in the first phase to thousands by phase 3 trials. Before it begins, there's pre-clinical work to understand the nuts and bolts of a disease. Human-study challenges add heaps of risk in speeding things up, and all those decisions have had to happen quickly.

Different models of development change how manufacturing gets under way. Consider both the Moderna and Pfizer-BioNTech ones, which are based on a genetic sequencing approach that hasn't previously been used. Instead of triggering an immune response like typical vaccines, these messenger RNA-based (mRNA) versions don't use live viruses and instead teach our cells how to respond. Good as that is for the future of health care, it's harder for regulators to expedite because it's new to them as well. They've had to squeeze timelines and start approval processes before finishing clinical trials.

Canada has put in place an interim order that allows manufacturers to submit data from trials as they're collected as opposed to submitting completed studies and data sets at the same time. The aim is to reduce administrative burdens in conducting a clinical trial while still maintaining patient safety and the validity of results. Health Canada said it would also introduce "flexibility by expanding the types of health care professionals who can conduct a clinical trial."

Several regulators have existing ways to go faster. For example, Japan's Pharmaceuticals and Medical Devices Agency has tools like priority review and conditional approval, which can shorten a timeline to around six to nine months. But the country has one of the lowest confidence rates in vaccination in the world and its approval processes are slow. In the late 1980s, close to 1,800 people suffered side effects like non-viral meningitis from the mumps, measles and rubella vaccine. The government had to pay damages and the vaccines were halted by 1993. However, the U.S. Centers for Disease Control and Prevention, along with medical regulators elsewhere, still recommend it.

That's precisely why if one national regulator deems a vaccine ready to use others won't necessarily follow along. They can also approach procedures differently. The FDA, for instance, gets all the raw data and runs its own tests. In Europe, each country has its own regulator and a central regional body relies on manufacturers' analyses of their own data. It can depend on why agencies were formed (for consumers or companies) and what they're responsible for.

Scientists worry expedited emergency approvals will pose problems for understanding long-term effects, according to a report in Nature. And there are other considerations, such as precedents for future vaccines and drugs. If it was done for Covid-19, why not for the next virus that looks like a pandemic, even if it doesn't end up being one? Slowing down the process once it's already gone into overdrive will be difficult.

Racial differences could mean that countries can't take efficacy data for granted. With Covid-19, one draft study showed that less than half of one percent of white participants didn't show an immune response to Covid vaccines, compared with around 10per cent of Asian-Americans. One of the authors noted their work pointed to the need for clinical trials to "carefully consider ancestry in their study designs to ensure that efficacy is measured across an appropriate population."

So what's the way forward? Freely exchanging data on open platforms has been suggested. Monitoring how people react over time will matter greatly to learn lessons for the future. But we're in an explosive pandemic, and while speed matters, so do safety and trust. (Bloomberg)