The coronavirus outbreak has now killed around 137,000, and infected more than 2 million people in 185 countries and territories, according to data by Johns Hopkins University.

Key points: Some Pacific Island nations were among the first to restrict entry from coronavirus hotspots

Some Pacific Island nations were among the first to restrict entry from coronavirus hotspots Comoros and Lesotho are the only two African nations to have not reported positive cases

Comoros and Lesotho are the only two African nations to have not reported positive cases In Turkmenistan the word coronavirus is banned

The pandemic first emerged as an unknown virus with symptoms similar to pneumonia in the Chinese city of Wuhan last December, before it spread to other nations at an alarming rate.

It has affected almost all corners of the globe, except for a small number of countries and territories that say they have not recorded any positive cases.

Countries with no reported COVID-19 cases: 1. Comoros 2. Kiribati 3. Lesotho 4. Marshall Islands 5. Micronesia 6. Nauru 7. North Korea 8. Palau 9. Samoa 10. Solomon Islands 11. Tajikistan 12. Tonga 13. Turkmenistan 14. Tuvalu 15. Vanuatu

Raina MacIntyre, biosecurity expert from the University of NSW and the Kirby Institute, told the ABC the lack of reported cases in these countries could be due to three contributing factors.

These are "poor surveillance systems and weak diagnostics public health infrastructure resulting in failure to identify cases, censorship of information for political reasons or to protect tourists, [and a] genuine absence of disease," she said.

Pacific Island nations locking down before cases emerge

Many of the 15 nations and territories are small Pacific Island nations including Kiribati, Marshall Islands, Micronesia, Nauru, Palau, Samoa, Solomon Islands, Tonga, Tuvalu and Vanuatu.

Across the Pacific, countries have been locking down or declaring national emergencies in response to COVID-19 — some even before recording a case of coronavirus.

Some Pacific Island nations were among the first to impose measures to contain the spread of the outbreak, including Solomon Islands, which was one of the first countries to restrict entry from coronavirus hot-spots.

Micronesia, Vanuatu, Kiribati, Nauru and Tonga have declared states of emergency, restricted activities and shut their borders.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 11 seconds 1 m 11 s Cyclone Harold devastates Vanuatu.

The health systems in several Pacific countries were already under strain and struggling even without a pandemic.

But the true nature of Pacific Islands' vulnerabilities came to light as Cyclone Harold left death and destruction in its wake, making coronavirus management more complex.

Vulnerable countries in the Pacific will likely be affected by any funding cut. ( WHO Western Pacific )

The region's population is dispersed across dozens of atolls and island groups that are sprawled across some 5,000 kilometres.

Pacific countries also face challenges including slow internet, extremely high operational costs and infrequent transport links.

The World Health Organisation (WHO) stated, "specialist and hospital-based care is limited to areas that are densely populated", which means people often have to travel great distances for basic health needs at a great cost.

Comoros and Lesotho: few international visitors

Lesotho is one of two African nations that claim to have no positive cases. ( Reuters: Siphiwe Sibeko )

The archipelago of Comoros off the south-east coast of Africa and the high-altitude landlocked Kingdom of Lesotho are the only African nations that have not reported any positive coronavirus cases.

This could be attributed to the geographical nature of both countries, and limited international visitors.

The WHO is very active in the Comoros. It said the country has very few bilateral partners, which puts it at a disadvantage in mobilising financial support for its health system.

The United Nations agency assisted in checking all arrivals for symptoms in January, and by March the President of Comoros Azali Assoumani announced restrictions on events and size of gatherings.

Lesotho's two million population is surrounded entirely by South Africa, where hundreds of people have tested positive for coronavirus.

Prime Minister Tom Thabane declared a state of emergency and announced a lockdown last month.

While Lesotho may not have confirmed cases, it also did not have testing capabilities until last month when 20,000 test kits were donated by Alibaba founder Jack Ma.

This week, local media reports around 23 samples have been sent for testing in South Africa and 18 have come back negative, while the rest are waiting for results.

State censorship preventing news of North Korean outbreak

A World Health Organisation representative said North Korea is still testing for coronavirus. ( AP: Korean Central News Agency/Korea News Service )

North Korea borders China, which has had 3,346 deaths and more than 83,000 confirmed cases and South Korea, which has had more than 10,600 cases and 229 deaths as of Thursday.

However, authorities there says the nation remains coronavirus free, despite it lacking a reliable healthcare system and neighbouring Asia's most infected countries.

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A World Health Organisation representative said the country was testing for coronavirus and had more than 500 people in quarantine, but still had no confirmed cases.

Doctors have said the country could conceal an outbreak through state censorship if one occurred.

Phil Robertson, deputy director of the Human Rights Watch Asia division, told the ABC, North Korea often asserts that "everything is perfect even when that is demonstrably not the case".

"It means any revelation to the contrary [of Kim Jong-un] is considered to undermine his leadership and must be punished," he said.

"By asserting that North Korea is free of COVID-19, the government can argue, however implausibly, it is uniquely better than other nations in Asia."

Mr Robertson said it's not clear if North Korea has done much about the pandemic.

"What is clear is North Korea's prisons, forced labour camps, political prisoner camps, and other places of detention are places where many suffer serious health problems already," he said.

"If COVID-19 gets into these facilities, prisoners will drop like flies."

Turkmenistan and Tajikistan shrouded in secrecy

Turkmenistan's President Gurbanguly Berdymukhamedov has banned the word coronavirus. ( Sputnik via Reuters )

Authorities in the central Asian nations of Tajikistan and Turkmenistan have insisted there are no cases of coronavirus in their respective countries.

Both nations are relatively isolated, with few travellers passing through, but they are also shrouded in secrecy.

Rachel Denber, Europe and Central Asia deputy director of the Human Rights Watch, told the ABC zero case reports in both countries are "almost certainly" the results of "concerted efforts to suppress information".

"Given both Governments' lack of credibility on data, and given migration flows, especially the flow of Tajik migrant workers from Russia … it is very difficult to believe claims that there is not a single case," Ms Denber said, adding that both governments are "repressive in their own specific ways", including by retaliating against journalists for speaking out against the coronavirus.

"One of the most important tools any government has in preventing the spread of COVID-19 is by ensuring a steady, free flow of accurate information," she said.

Turkmenistan, which borders Iran, is one of the world's most closed-off countries, with RSF ranking it last in its World Press Freedom Index in 2019.

The word coronavirus is banned altogether in the country and people can be arrested for wearing a face mask, according to Reporters Without Borders (RSF).

Its autocratic President Gurbanguly Berdymukhamedov has ruled since 2006 through an all-encompassing personality cult that styles him as Turkmenistan's "arkadaq", or protector.

In Tajikistan, authorities have reportedly blocked independent news outlets that reported on what they believed to be a coronavirus case in the country's north.

There are also reports Turkmen authorities have warned people, including doctors, to not talk about what's happening in hospitals, Ms Denber said.

"Silencing doctors is especially alarming," she said.

"If doctors can't speak freely about, for example, their own need for protective equipment, or test kits, ventilators … this will almost certainly harm their ability to get the tools they need to treat patients."