What is 'Havana syndrome', due to which Kamala Harris' trip to Vietnam was delayed?

Washington: The phrase "anomalous health incident" is used to describe the so-called "Havana syndrome" psychogenic illness that has sickened diplomats in several countries.

US Vice President Kamala Harris' flight from Singapore to Vietnam was delayed by three hours on August 25 after an "anomalous health incident" took place in Hanoi, the US embassy said.

The phrase "anomalous health incident" is used to describe the so-called "Havana syndrome" psychogenic illness that has sickened diplomats in several countries.

Here's an explainer to understand what is Havana Syndrome

The US government uses anomalous health incidents to describe the Havana syndrome. Some of those impacted report hearing a loud piercing sound and feeling intense pressure in the face. Pain, nausea, and dizziness sometimes followed.

Similar, unexplained health ailments have since been reported by Americans serving in other countries, including Germany, Austria, Russia and China.

U.S. officials "take any reported incident of Havana syndrome seriously,” press secretary Jen Psaki said at a White House press briefing on August 25.

What causes Havana syndrome?

The US is still unsure of what causes the Havana syndrome five years after the first case in Cuba when US diplomats and their families complained of nosebleeds, migraines, and nausea after experiencing piercing sounds at night.

Since then, similar complaints have been reported by US officials in China, Russia, and inside the United States.

The problem has led to unproven allegations that Russians or others used sonic or other high-intensity electronic devices to physically harm US diplomats.

As per an AP report, at least two possible incidents were reported in the Washington area, including one case near the White House, in November 2020 in which an official reported dizziness. Administration officials have speculated that Russia may be involved, a suggestion Moscow has denied.

Scientists and government officials aren't yet certain about who might have been behind the attacks and if the symptoms could have been caused inadvertently by surveillance equipment.

The administration is providing assurances that it takes the matter seriously, is investigating aggressively and will make sure those affected have good medical care.

One key analysis identified directed, pulsed radio frequency energy as the most plausible culprit.

Published in December by the National Academy of Sciences, the report said a radio frequency attack could alter brain function without causing gross structural damage. But the panel could not make a definitive finding on how U.S. personnel may have been hit.

And a declassified 2018 State Department report cited a lack of senior leadership, ineffective communications, and systemic disorganization in responding to the Havana cases.

The report says the cause of the injuries was currently unknown. The document was published by George Washington University's National Security Archive.

Investigations into Havana syndrome

Congress has raised alarms over such attacks, finding rare bipartisan support in the House and Senate for a continued government-wide investigation into the syndrome response as well as millions in support for American personnel medical monitoring and treatment.

The number of reported cases of Havana syndrome has sharply grown, posing a challenge for the Joe Biden administration.

US senators had in May said that the government was investigating an apparent increase in mysterious directed-energy attacks.

Avril Haines, director of national intelligence, and CIA Director Bill Burns are also investigating a growing number of reported injuries and illnesses possibly linked to directed energy attacks.

The CIA also recently appointed a new director of its task force investigating Havana syndrome cases, an undercover official who participated in the hunt for Osama bin Laden.