Volume 30, Number 5—May 2024
Dispatch
Interventional Study of Nonpharmaceutical Measures to Prevent COVID-19 Aboard Cruise Ships
, Leonidas Kourentis, Lemonia Anagnostopoulos, Michalis Koureas, Maria Kyritsi, Katerina Maria Kontouli, Fani Kalala, Mattheos Speletas, and Christos Hadjichristodoulou
Table
COVID-19 health measures, laboratory screening, and diagnostic testing for SARS-CoV-2 per comparison population group in interventional study of nonpharmaceutical measures to prevent COVID-19 aboard cruise ships*
| Variable | Comparison population groups |
||
|---|---|---|---|
| Group 1: cruise ships A and B sailing in EUMS waters | Group 2: 9 cruise ships sailing in EUMS waters | Group 3: EUMS/EEA community populations | |
| Mask wearing |
Unmasked passengers, masked crew† |
Masked passengers and crew |
Policies varied |
| Physical distancing‡ |
N |
Y |
Policies varied |
| Daily body temperature measurement for passengers and crew |
Y |
Y |
NA |
| Pre-embarkation health screening questionnaire for passengers and crew§ |
Y |
Y |
NA |
| Quarantine measures for close contacts of SARS-CoV-2–positive passengers and crew members |
Y |
Y |
Yes |
| Buffet line allowed in food service areas¶ |
Y |
N |
NA |
| >95% passengers and crew members vaccinated# |
Y |
Y |
Vaccine coverage varied in EUMS |
| Serologic testing for crew members |
Y |
N |
NA |
| End of voyage reporting by cruise line to competent authorities for COVID-19 surveillance data |
Y |
Y |
NA |
| Other NPMs: education and training; restrictions for population density, excursions, and port visit; policy enforcement |
Y |
Y |
Policies varied** |
| Screening/diagnostic testing for crew members | |||
| All crew members already onboard the cruise ship tested by RADT within 1 wk before resuming operations | Y | Y | NA |
| Day of embarkation RADT | Y | Y | NA |
| Routine RADT |
Every 7 d |
Every 7 d |
Varied among EUMS |
| Screening/diagnostic testing for passengers | |||
| Day of embarkation RADT | Y | Y | NA |
| RADT before disembarkation | Y | Y | NA |
| Nonvaccinated (or not fully vaccinated) passengers tested by RADT on day 3 or 4 of cruise†† | Y | Y | NA |
*See Appendix (https://wwwnc.cdc.gov/EID/article/30/5/23-1364-App1.pdf) for more detailed information about definitions and methods used in the study. EEA, European Economic Area; EUMS, European Union member states; NA, not applicable; NPM, nonpharmaceutical measures; RADT, rapid antigen detection test. †All passengers wore masks on 1 voyage in which elevated number of cases occurred in cruise ship A. ‡Physical distancing of 1.5 m. §Information collected included demographic information (name, date/time of itinerary, port of disembarkation, cabin number, contact telephone number for 14 d after disembarkation), health questions regarding the past 14 d (presence of COVID-19 compatible symptoms, close contact of COVID-19 case, and whether person provided care was in close proximity, traveled on conveyance, or shared household with SARS-CoV-2–positive person). ¶Group 1 ships provided meals as sitting service and in a buffet line with strict hand hygiene measures, sneeze-guards, replacement of serving utensils, and food service by crew. Group 2 ships provided meals in a sitting service and not in a buffet line. Both groups applied the same rules about handwashing, maximum number of persons in food service areas, and distancing of tables and chairs. #Persons were considered fully vaccinated 14 d after the last dose of a COVID-19 vaccine. **Other measures applied in the community: gathering restrictions with maximum capacities, masking and physical distancing in indoor public spaces (theaters, gyms), hybrid policies for education and workplace settings, and proof of vaccination or negative tests to attend events (2). ††During the study period, the cumulative vaccine uptake (%) in the total population in EUMS/EEA (group 3) was ≈66% for the primary course (3).