THE HAGUE – Dutch government officials warned as early as May 2021 that Curaçao's reported COVID-19 vaccination rates might not accurately reflect the proportion of people living on the island who had been vaccinated. The concern centered on the unknown number of undocumented residents, which made it difficult to determine the actual size of the population during the pandemic.
The warning was documented in internal correspondence from the Dutch Ministry of Health, Welfare and Sport (VWS), dated May 11, 2021.
At the time, Curaçao was in the midst of its vaccination campaign, which had begun in February 2021. The island had recently experienced a severe wave of COVID-19 infections, and vaccination was considered an important tool in controlling the pandemic and eventually easing restrictions.
However, according to the internal correspondence, the vaccination percentages being reported could provide an incomplete picture of the situation.
The problem was not necessarily the number of vaccinations administered, but the population figures used to calculate vaccination coverage.
Official vaccination percentages were generally calculated using the number of registered residents. Yet Curaçao also had an undocumented population whose actual size was unknown.
This meant that the percentage of vaccinated registered residents could differ from the percentage of vaccinated people among everyone physically living on the island.
For example, if authorities reported that 70 percent of registered residents had been vaccinated, that figure did not necessarily mean that 70 percent of all people living in Curaçao had received a vaccine.
Although vaccinations administered to undocumented residents were recorded, authorities lacked reliable information about the total number of people belonging to that group.
Without an accurate population estimate, calculating the vaccination rate for the entire island remained difficult.
Uncertainty During a Critical Period
The warning came at a particularly sensitive moment for Curaçao.
Following a serious COVID-19 outbreak, residents were dealing with restrictions intended to reduce infections and prevent further pressure on healthcare services.
Vaccination coverage was closely followed by the government, healthcare professionals and the public because it was viewed as an important indicator of progress in the fight against the virus.
Higher vaccination rates also contributed to discussions about when restrictions could be relaxed.
However, the internal correspondence raised questions about how accurately the published percentages represented the population as a whole.
The uncertainty was especially relevant because undocumented residents were not necessarily included in the official population figures used to calculate vaccination rates.
As a result, residents following the vaccination statistics might have assumed that the reported percentages applied to everyone living on the island, even when that was not necessarily the case.
The correspondence also indicated that international comparisons could be misleading.
Organizations such as the World Bank and Worldometer sometimes used population estimates that differed from the figures applied by local authorities.
Consequently, vaccination percentages calculated using different population estimates could produce different results, even when the underlying number of vaccinations was the same.
Dutch Authorities Were Aware of the Problem
According to the correspondence, the warning issued on May 11, 2021, was shared with officials involved in the vaccination campaigns on the islands.
The information was also forwarded to then-Dutch State Secretary for Health, Welfare and Sport Paul Blokhuis.
This indicates that the uncertainty surrounding vaccination coverage was known to officials in both the Netherlands and the Caribbean countries during the early stages of the vaccination campaigns.
However, the correspondence does not establish that Curaçao deliberately published incorrect vaccination figures.
Nor does it demonstrate that government decisions concerning COVID-19 restrictions were based on inaccurate information.
Instead, the documents highlight an important statistical limitation that could affect how vaccination coverage was interpreted.
The central issue is whether the public was sufficiently informed that reported vaccination percentages did not necessarily represent the entire population physically residing in Curaçao.
Five years after the pandemic vaccination campaign began, the correspondence provides additional insight into the challenges authorities faced when attempting to measure vaccination progress in a population whose exact size was not fully known.