In the middle of the summer, the battle plan to stop the fourth wave was ready. The RIVM had worked on it, the GGDs had drawn up a ‘Roadmap Q3’ for the best deployment of staff. But even before that plan was on the desk of outgoing minister Hugo de Jonge (Public Health, CDA), the wave had already started – and in no time there was no stopping it.
The plan looked like this. This summer, just like last year, the number of infections had to fall sharply – to a maximum of a few dozen positive tests per day.
New outbreaks would then be and remain local. Flare-ups of the virus would be quickly detected via measurements in the sewage water – infected people excrete virus particles in their stools. Then the GGDs would dive right on top of that neighbourhood: everyone would receive an invitation to be tested and an intensive search would have to be carried out for undiscovered infections. The source and contact investigation had to be able to link each patient to a known source of infection.
But that plan was based on a fourth wave in the fall and not in July. The cabinet had recently decided that nightclubs were allowed to open again and festivals were also allowed again. That was possible, it was thought, because visitors would be tested for access. But it turned out that there were big holes in that system to prevent outbreaks. Even before the plan to prevent a new wave could be implemented, the number of infections increased rapidly.
There were also problems with crucial parts of the plan: an increase in the number of virus particles in the sewage was only detected after the number of positive tests had already exploded. The delay was due to the fact that this research takes a relatively long time. Another problem was that people who were tested sometimes had to wait a long time for their results because the labs were very busy. And source and contact investigations soon had to be limited because the GGDs could not cope with the large influx of infected people.
Will the battle plan for the autumn be sufficient, when the respiratory infections season starts again, life takes place indoors more often and the virus spreads more easily?
The plan is good, says Susan van den Hof, head of the Center for Epidemiology and Surveillance of Infectious Diseases at RIVM, but it was unsuitable for the situation in the summer. The RIVM thinks that during a next wave the number of infections will be very low and there will be local outbreaks. “They can be seen faster in the sewers, because then you also take people with you who do not have themselves tested. If there are only local outbreaks, the GGDs must be able to handle the investigation.”
Also read: ‘Draining the virus with source and contact research is no longer realistic’, says the GGD
There is also hope that new working methods will speed up contact investigations. There is already an example of that. Because a single GGD hardly had to limit the source and contact research this summer. In the GGD region of Utrecht, the investigations were carried out almost completely and about 1,300 ‘cases’ were handled per day. “Because we had the experience of last year, when the number of infections suddenly increased so much, we decided to innovate this process,” explains a spokesperson.
The Utrecht GGD works with a digital system, Coronacare. Young people under the age of thirty – the largest infected persons in the latest wave – were called once and asked to complete an online questionnaire about where they had been and with whom they had contact. This is how GGD and RIVM kept an eye on the sources of infection. In the time saved by source and contact researchers, the elderly and other risk groups could be called. „We have noticed that this digital process is a very efficient method, suitable for the target group.
This autumn, all GGDs must make a technological leap. HPZone, the outdated software currently used by the GGDs for source and contact investigations, will then be replaced by its own system. With an app, GGD Contact, people who have tested positive can make an inventory of who they have been close to during their contagious period. Their contact details can be shared with the GGD via the app, which is expected to save a lot of time. All GGDs must use the new system before the end of September.
Read more about the source and contact investigation issues: Nothing to do for the GGD flex workers, in the middle of the pandemic
How well the plan will work to stop a potential fifth wave will depend in large part on vaccination coverage. Van den Hof: “We have now seen again how quickly the virus can spread among unvaccinated groups.”
Parties in nightclubs and festivals may be allowed again if vaccination rates are higher. The rules for testing for access have already been tightened: a negative test can be up to 24 hours old, instead of 40 hours. However, Van den Hof warns: the vaccines seem to protect less well against the Delta variant. “You have to think seriously about how festivals can still be organised. Maybe you should have vaccinated people tested before they are allowed in as long as not everyone has had the chance to be fully vaccinated.” Many young people have only been vaccinated once.
The peak of the fourth wave also showed good news: the infected young people infected few elderly people. “The vast majority of people who became seriously ill had not been vaccinated,” adds Van den Hof. “There were also more positive tests in nursing homes, but that increase was nothing compared to what we have already seen. That is encouraging, because most infections were already caused by the Delta variant at that time.”
A version of this article also appeared in NRC on the morning of August 11, 2021