THE HAGUE – Aruba and Curaçao faced a significant challenge in determining their actual COVID-19 vaccination coverage during the pandemic because neither island knew precisely how many undocumented residents were living within its borders. Internal correspondence from the Dutch Ministry of Health, Welfare and Sport (VWS) reveals that officials warned about the problem in May 2021, raising concerns about the reliability of vaccination percentages and international comparisons.
The warning, dated May 11, 2021, came approximately three months after both Caribbean countries began their vaccination campaigns in February of that year.
At the time, vaccination rates were receiving considerable attention as governments attempted to control the spread of COVID-19 and determine when restrictions on daily life could be eased.
Curaçao had recently experienced a severe wave of infections, while Aruba was also dealing with significant public health restrictions.
For both islands, the progress of vaccination campaigns was an important part of the public discussion about returning to normal economic and social activity.
However, Dutch officials identified a statistical problem that complicated efforts to determine how much of the population had actually been vaccinated.
Different Population Figures Created Uncertainty
The main difficulty involved the number of people living on the islands.
Both Aruba and Curaçao maintained official population registers, but those figures did not necessarily include all undocumented residents.
Because the size of the undocumented population was unknown, authorities could not calculate with certainty the proportion of the total population that had been vaccinated.
The islands recorded vaccinations administered to undocumented residents, but this information alone was insufficient to establish vaccination coverage within that group.
To calculate a vaccination percentage accurately, authorities need both the number of people vaccinated and a reliable estimate of the population being measured.
If the total population is underestimated, the reported vaccination percentage can appear higher than the actual proportion of residents who have received a vaccine.
For example, a vaccination rate of 70 percent among officially registered residents would not automatically mean that 70 percent of everyone physically present on an island had been vaccinated.
The uncertainty also complicated comparisons with other countries.
According to the Dutch correspondence, international organizations, including the World Bank and Worldometer, used population figures that differed from those applied by Aruba and Curaçao.
As a result, published vaccination percentages could vary depending on which population estimate was used.
This meant that comparisons between the islands and other countries needed to be interpreted carefully.
Implications for Pandemic Policy
During the pandemic, vaccination rates were among the indicators used to assess the progress of vaccination campaigns and inform public discussions about restrictions.
Residents hoped that increasing vaccination coverage would eventually allow governments to relax curfews, lockdowns and other measures introduced to limit the spread of COVID-19.
However, vaccination coverage was not the only factor considered in pandemic policy. Infection rates, hospital admissions and pressure on healthcare services were also relevant.
The uncertainty identified by Dutch officials therefore did not necessarily mean that governments were making incorrect decisions.
Instead, it meant that one of the indicators being closely followed by the public had limitations that required explanation.
For residents, the distinction was important because published vaccination percentages could create an impression of broader population coverage than the available information could establish.
Warning Reached Senior Dutch Officials
The internal warning was circulated on May 11, 2021, and shared with officials involved in the vaccination campaigns on Aruba and Curaçao.
It was also forwarded to Paul Blokhuis, who was serving as Dutch State Secretary for Health, Welfare and Sport at the time.
The correspondence demonstrates that Dutch authorities were aware of the difficulty of determining vaccination coverage when part of the population was not included in official population records.
However, the documents do not prove that either Aruba or Curaçao intentionally misrepresented its vaccination figures.
They also do not establish that specific pandemic restrictions were introduced or lifted on the basis of misleading statistics.
What the correspondence does show is that officials recognized the limitations of the available data while vaccination campaigns were underway.
The revelations raise a broader question about how governments communicate public health statistics when the underlying population figures are uncertain.
For Aruba and Curaçao, the experience illustrates the importance of reliable population estimates, particularly during public health emergencies when governments must make decisions affecting the entire population.
The documents also highlight the need to explain clearly which population groups are included in official statistics so that residents can better understand what the reported figures actually represent.