The measures implemented in the Netherlands during the COVID-19 crisis were effective against the spread of the SARS-CoV-2 virus. This is the outcome of a study conducted by RIVM. The measures consisted of vaccinations and other measures aimed at preventing transmission of the virus. Both types of measures helped to reduce the number of infections. The results of this study will be helpful in providing rapid advice on measures and policy in the event of a subsequent major outbreak of disease. 

Effectiveness of other measures can only be assessed in packages 

In addition to vaccination, the government adopted other measures to ensure that fewer people could infect others, for example by reducing physical contact. It is not possible to investigate how effective these measures were individually, since multiple measures were often in effect simultaneously. However, it is possible to look at the different packages of measures. 

 Timing of measures is very important 

With regard to the packages of COVID-19 measures implemented in the Netherlands, the study shows that the effectiveness increased proportionate to the intensity of the measures. The timing of the measures was also very important. If the package of measures at the onset of the first COVID-19 wave had been implemented three days later, that would have led to more than double the number of daily deaths during the peak. 

 Different strategy, less success 

What if the Netherlands had opted for a different strategy to combat the outbreak during the first wave? RIVM researchers ran the numbers for this scenario using an established British calculation method. They compared the Dutch strategy to the strategies used in Belgium, Denmark, Germany, the UK and Sweden. The results showed that the number of deaths in the Netherlands would have been more than double with a different strategy. 

 Protection resulting from vaccines 

In the Netherlands and internationally, various studies were conducted on vaccine-induced protection against COVID-19. These studies show that the vaccines are effective in preventing infection. Vaccinated people were less likely to become ill from the coronavirus SARS-CoV-2 than unvaccinated people. They were also less likely to transmit the virus to others. Moreover, vaccinated people were much less likely to end up in hospital or die as a result of COVID-19. 

Advisory recommendations for composing measures 

The study yielded a number of advisory recommendations for composing packages of measures in response to a future epidemic. One of these recommendations is to collect certain data on people who are infected. This includes the most likely source of infection, the most likely time of exposure, and the first day of illness. This will allow us to determine the time between exposure and illness, as well as the interval between when the first person was infected and when the next person was infected. 

Another recommendation is to gain a clear understanding of contact patterns and human movements in good time. This is necessary in order to more accurately determine the impact of measures on the spread of disease. 

 Calculation methods 

The report offers more information on the calculation methods used here. RIVM also shares the dataset used in the study, so other scientists can conduct further research on the same data.