The World Health Organization (WHO) has called on countries not to issue COVID-19 "vaccination passports," or vaccination certificates, saying public health risks remain even after inoculation.

WHO also admonished governments not to introduce vaccination passports as a condition of entry for international travel since there are still uncertainties regarding the effectiveness of vaccinations.

"Being vaccinated should not exempt international travelers from complying with other travel risk reduction measures," said the WHO Emergency Committee in a statement.

WHO has long held that vaccinated people should still practice the proven mitigation measures of frequent hand washing, mask wearing and keeping a safe social distance from other people. Vaccinated people are not exempt from these measures, according to WHO.

WHO's strong opposition to vaccination passports follows news the European Union is considering this document as a mandatory travel requirement among its 27 member states.

European Commission (EC) President Ursula von der Leyen still supports a vaccination passport, which might be used by the EU member states as a joint certificate to identify all persons vaccinated against COVID-19.

"It is a medical requirement to have a certificate proving that you have been vaccinated," she pointed out.

On the other hand, she believes EU member states should first discuss any plan making vaccination passports a condition for international travel.

The EC said talk of using vaccination certificates to allow greater travel and tourism within the EU is "premature" at this stage. It did, however, leave the door open for plans to be implemented in the future.

"We feel that now this is the time for these vaccine certificates to be recognized across the European Union, and even beyond the European Union." said EC vice president Margaritis Schinas.

Schinas said it's "perfectly imaginable that this can open avenues for other use, including facilitating travel."

EU heads of state and governments will have to agree to the idea and enough Europeans would have to be vaccinated first, he said.

The EU first needs to agree on common criteria for this passport. The EC, which is the executive arm of the EU, said the EU will have to agree on the minimum data necessary for the vaccination certificate and ensure it will respect data privacy laws.

This common approach could be "scaled up globally" and might become a model for certification systems of WHO.

EU member states must accelerate their vaccination programs before any serious talk about vaccination passports, however.

The EC said member states should set ambitious targets to vaccinate at least 80% of health and social care professionals and people over 80 years old by March 2021. A minimum of 70% of the total adult population should be vaccinated this summer.