TORONTO -- Canada has become the latest country to announce it would begin using a contact tracing smartphone application to help mitigate the spread of COVID-19.

Prime Minister Justin Trudeau told reporters Thursday that the “completely voluntary” app will be available in early July to any Canadian that wants it. It uses Bluetooth connectivity to track when two devices come in close contact with each other and if a user tests positive for the virus, the app will notify anyone that had come in close contact with that person’s phone.

While contact tracing apps have been rolled out elsewhere,not every country’s app has had a smooth roll out.

Here are four takeaways from other countries that have developed contact tracing applications:

PRIVACY CONCERNS ABOUND

The big concern with these apps internationally is privacy. A study this week from Amnesty Internationalexamined 11 contact tracing apps from Europe, north Africa and Asia, and found some of the apps are “putting the privacy and security of hundreds of thousands of people at risk.”

The organization found Bahrain’s “BeAware Bahrain,” Kuwait’s “Shlonik” and Norway’s “Smittestopp” apps to be particularly troubling for the users’ privacy, as they use GPS data and allow for real-time tracking of its users. Norway has since paused the use of its app.

“The Norwegian app was highly invasive and the decision to go back to the drawing board is the right one,” Claudio Guarnieri, head of Amnesty International’s Security Lab, said in a news release. “We urge the Bahraini and Kuwaiti governments to also immediately halt the use of such intrusive apps in their current form.”

Trudeau said Thursday that the privacy of Canadians “will be fully respected,” and that location services would not be used for the app, meaning it would not use real-time movement tracking.

Amnesty International added that apps using a decentralized model of Bluetooth contact tracing, such as Canada’s, “tend to be less concerning from a privacy perspective.”

MADE POSSIBLE BY GOOGLE AND APPLE

Similar to Canada’s app, Google and Apple are involved in several of the contact tracing applications around the world.

In May, both companies released a software tool that allows developers to use the Bluetooth capability of smartphones to detect each other, while also maintaining the user’s privacy.

Switzerland, Germany and Italy have already launched apps based on this model. Last month, Apple and Google said that health agencies from 22 countries and U.S. states are using the tool to develop their own app.

Canada’s app, while developed by Shopify, Blackberry and the Government of Canada, is also using this tool from Google and Apple.

Applications using this software tool could help in the long term with international travel, as each country’s app could in theory communicate with each other.

QUESTIONS ABOUT EFFECTIVENESS

While many countries are just now rolling out their apps, some countries that have had them since earlyspring now say they weren’t exactly the game changer that they had hoped.

In Iceland, developers launched “Rakning C-19” in early April and it was quickly downloaded by 38 per cent of the population, but its impact has been minimal.

“The technology is more or less … I wouldn’t say useless,” Gestur Pálmason, a detective with the Icelandic Police Service overseeing contact tracing efforts, told the MIT Technology Review. “I would say [Rakning-19] has proven useful in a few cases, but it wasn’t a game changer for us.”

A study out of the University of Oxford inApril, shows that contact tracing apps can help stop an epidemic, but only if approximately 60 per cent of the population uses it.

In Singapore, “TraceTogether” launched in April, but its lead developer was quick to temper expectations surrounding the product.

In a blog post, Jason May said the app would not be a “panacea” for the spread of the virus and that it is only meant to complement the existing tracing efforts.

“You cannot ‘big data’ your way out of a ‘no data’ situation. Period,” May wrote in the post.

NOT A PRIORITY FOR SOME COUNTRIES

In the United Kingdom, a contact tracing app had been a focal point of its response to the virus, with an initial plan to release their app in mid-May, but now the British government has said it won’t be ready before winter.

The U.K. government had intended to develop an application without the help of Apple and Google’s software tool, but have now change their minds. The government added that the delays are simply because it is no longer a priority, as they’ve noticed that people would rather hear any potential bad news from a human voice, rather than a notification on their phone.

“One of the things it has taught us is that it is the human contact that is the one most valued by people,” James Bethell, the minister for innovation at the Department of Health and Social Care, told the U.K.’s Science and Technology Committee on Wednesday.

“In fact, there is a danger of being too technological and relying too much on text and emails and alienating or freaking out people because you’re telling them quite alarming news through quite casual communications.”

In the United States, a survey from Avira indicates that more than 71 per cent of Americans would not download a contact tracing app if it were an option.

With files from CTV News Ottawa News Bureau Online Producer Rachel Aiello