By Lee San

At the Kenyan border post, we were lining up to enter Tanzania. Lai and I were nevertheless stopped at the checkpoint because we failed to produce our yellow fever vaccination certificates, which were actually inside our checked baggage.

Yes, that's a yellow color 16-page booklet issued since 1969 by the WHO. Each jab is valid for ten years. The thing is, the certificate guarantees us free passage to 43 African countries as well as those in South and Central America. Without this yellow booklet, you could be denied entry into any of these countries or get stranded at the immigration checkpoint for hours, holding up the whole group.

But why do we need a yellow fever vaccination certificate to visit African and Latin American countries?

Yellow fever was a lethal killer among humans and primates in Africa from the 17th through 19th centuries. Later due to the transatlantic slave trade and migration, it spread far and wide to Latin America and the Caribbeans to become a local epidemic. Back then yellow fever was very easily spread through the Aedes mosquitoes with extremely highly fatality rates, and could potentially wipe out the entire population of a village, even the whole contingent of 400,000 French troops!

Fortunately in 1938, South African virologist Max Theiler successfully developed a vaccine against the yellow fever virus. He was awarded the Nobel Prize in Medicine in 1951 for saving countless human lives.

Even until this day yellow fever can only be prevented but not cured. Today, there are more than 200,000 people infected with the virus every year, over 30,000 killed.

In order not to get infected in Africa, we reminded all our customers to get inoculated against yellow fever 15 days before departure, which was the best and probably the only option we had. Moreover, WHO would never want travelers to carry the disease to tropical Asia!

There are numerous pandemic viruses that have blocked the free movements of humans at certain points in history. Smallpox, for instance, claimed the life of Egyptian Pharaoh Ramesses V some 3,000 years ago, along with those of innumerable travelers and learned scholars.

Luckily, the airborne virus was eventually stopped by the vaccine. Smallpox was declared extinct by the WHO in 1980.

Sadly, the Black Death that ravaged the world between the 14th and 19th centuries was even more deadly. Like smallpox, it also became extinct and a part of our tragic history.

Additionally, the much dreaded Spanish flu infected some 500 million people worldwide in the two years from 1918 to 1920, killing at least 17 million, and was veritably the single most fatal pandemic in human history.

Something closer to my heart, the 2002 SARS outbreak almost paralyzed the entire travel industry. I can still remember all the empty seats on the plane. Indeed, everyone tried to shun public transport wherever possible back then. The tourist industry was completely halted, and I was momentarily out of work!

Barely 19 years later, today we are confronting yet another enormous catastrophe on an epic scale. But I can say for certain that the UN and WHO will very soon issue another booklet to travelers around the world, the COVID-19 vaccination certificate.

This vaccine is going to be the last straw, and indeed one and only remedy that will resuscitate our dying travel industry! Under the new normal, one will have to be immunized first before talking about traveling!

Seeing that the coronavirus vaccines have now been deployed to all corners of the world while more and more people get inoculated, there is a strong likelihood humanity will eventually break the infection chain and put a decisive end to this bloody pandemic. This will open up our world once again, normalizing our day-to-day lives and travels and bringing the tourist economy back to life.

In addition to the WHO vaccination certificate, the International Air Transport Association (IATA) will also introduce the IATA Travel Pass (ITP) to ensure all boarding passengers are immunized. But in the end, some countries may have their own criteria. They may appraise and decide to whom they should open their doors.

Perhaps nation-to-nation relationships and a country's overall performance in tackling the virus will have a say in post-vaccination days!

Anyway, the advent of the coronavirus vaccines is definitely a cause for celebration, as the struggling travel industry begins to see light at the end of the tunnel. Very soon this whole thing will be put behind us and we will get to travel once again!

This war with the virus has gravely bogged down the progress of humanity, throwing us back many years. US experts say average human lifespan will be shortened by one year. Hopefully this disaster will end very soon and will never ever come back again.

Actually, what I'm more worried about is the invisible "online virus warfare" that no vaccines could ever stop!

P/S: Kindly be reminded that after you get the jab, do keep in good order the official receipt issued by the authorities for the purpose of WHO/ITP certificate application in future. The receipt must bear the information such as date and place of inoculation, as well as vaccine manufacturer and code.

(Lee San is Founder and Group Executive Chairman of Apple Vacations. He has traveled to 132 countries, six continents, and enjoys sharing his travel stories and insights. He has also authored five books.)