(2:30 p.m. EST) -- Crystal will require all passengers on its ocean and river cruises to be fully inoculated with a COVID-19 vaccine at least 14 days prior to embarkation.Passengers will be required to provide proof of vaccination before embarking and must have received both doses of the vaccine (if recommended by the manufacturer) by that timeline.Crystal made the announcement Thursday as part of its Crystal Clean+ 4.0 health and safety initiatives, which also mandate negative COVID-19 tests for all passengers and crew; temperature checks at the terminal prior to embarkation; a "nimble" masking policy; physical distancing measures; enhanced cleaning and disinfection procedures, and reduced passenger capacity across the fleet.In outlining the company's decision to mandate vaccinations for all passengers against COVID-19, the company cited a survey by Cruise Critic earlier this month showing that a majority of respondents -- 81 percent -- said they would cruise if proof of vaccination were required.Only five percent of 3,000 respondents said they would not cruise if a COVID-19 vaccine were to be mandated."We are encouraged by the progress being made with the COVID-19 vaccines and what this means for our Crystal Family and the travel industry as a whole as we eagerly look forward to exploring the world again," said Crystal's interim president and CEO, Jack Anderson."We know that peace of mind is the greatest luxury; and the vaccine requirement is simply the best way to ensure the safest possible Crystal Experience for all on board. This sentiment is underscored by conversations with our guests and travel partners and a recent Cruise Critic survey of cruisers that revealed that more than 80 percent of respondents would cruise if a vaccine were required."Crystal joins a number of other lines, including UK-based Saga Cruises and American Queen Steamboat Company, in mandating proof of COVID-19 vaccination for all passengers.Crystal says it is aware the availability of COVID-19 vaccines varies according to country and state or provincial level. In a press release, Crystal noted it has voluntarily paused all operations through May 2021 for its river fleet; into June for its ocean ships; and through August 1 for Crystal Esprit and all of August for Crystal Endeavor.Proof of COVID-19 vaccination will be required across all ships, and all brands, in the Crystal fleet.Crystal will also be mandating vaccinations for crewmembers but acknowledges this may not be possible due to their age and country of residence. Younger citizens are often at the back of the line in most countries' roll-out plans. Until then, Crystal plans a strict testing regimen for all crewmembers."As part of the company's Crystal Clean+ 4.0 measures, crew members will be tested for COVID-19 prior to leaving their home location to join the ship and must receive a negative result. They also will take a COVID-19 test at embarkation; quarantine for seven days upon arrival; be tested again at the end of that seven-day period and must receive a negative result before beginning their duties," Anderson said. "When vaccines are widely available, they will be a requirement of employment for crew which must be completed at least 14 days prior to service."In addition to providing verified proof of COVID-19 vaccination at embarkation, passengers will also be required to complete an online form acknowledging the need for proof of vaccination. Cruise tickets will not be issued until travelers agree to those conditions.Crystal has published a PDF of frequently asked questions that can be
downloaded here.Cruise Critic is maintaining a regularly updated list of cruise lines requiring proof of COVID-19 vaccination.