Vaccines less effective against Delta variant, still the best line of defense: experts

The Covid-19 vaccines are proving to be less effective against the highly contagious Delta variant of the coronavirus - 9 percent of Netherlands residents that tested positive for the coronavirus last week, were fully vaccinated. It is not unexpected that the vaccines don't completely protect against a coronavirus infection, and they are still the best line of defense in this pandemic, experts said to NOS.

Vaccines never offer 100 percent protection and it was already known that this was the case for the coronavirus vaccines, virologist and Outbreak Management Team member Marion Koopmans said.

Clinical studies showed that the Pfizer and Moderna vaccines reduced the risk of infection by about 95 percent, AstraZeneca and Janssen by about 70 percent. And those percentages were established before other coronavirus variants started circulating. The now dominant Delta variant is extra contagious and all vaccines appear to be at least somewhat less effective in protecting against infection with this mutation.

But the vaccines still protect people from getting seriously sick from Covid-19, the respiratory disease caused by the coronavirus, and that is the important part. Eventually, everyone who wants to be vaccinated against the coronavirus will be fully vaccinated. And once that point is reached, measures against the spread of the virus can be scrapped. "But in the Netherlands, it is still too early for that," Koopmans said.

"Right now, there are still many gaps in our vaccination program," field epidemiologist Amrish Baidjoe said to the broadcaster. So if vaccinated and unvaccinated people come together, the first group could infect the second, more vulnerable group. And there is still a large group of unvaccinated people in the Netherlands. Like public health institute RIVM, Baidjoe believes that the basic measures against the spread of the virus - social distancing, get tested if you have cold-like symptoms and when you return from abroad, regularly wash your hands - should therefore continue to apply to fully vaccinated people for the time being.

According to Baidjoe, communications about the vaccines were too optimistic from the start. "We have to be realistic about what vaccines do an what the uncertainties are. Vaccines are and will remain our most important line of defense, but it is not a silver bullet. It does allow us to take lighter measures, so it is important get more people vaccinated," he said. "The higher the vaccination rate, the lower the transmission will be and the more will be permanently possible."