The U.S. military launched a secret campaign against China's COVID-19 vaccines during the pandemic, which aimed to cast doubt on the safety and efficacy of vaccines and other life-saving aid that was being supplied by China to the Philippines, a nation hit especially hard by the deadly virus, according to a recent Reuters investigation.

Reuters found at least 300 accounts on X, formerly known as Twitter, impersonating Filipinos, decrying the quality of face masks, test kits and the first vaccine that would become available in the Philippines, China's Sinovac. 

Almost all accounts were created in the summer of 2020 and promoted the hashtag #Chinaangvirus, a smear directed at China in Tagalog, equating the country to the virus.

X removed the profiles after Reuters asked about them, determining that the accounts were part of "a coordinated bot campaign" based on their activity patterns and internal data.

This operation was not previously reported.

According to the Reuters investigation, the military program started under former U.S. President Donald Trump and continued months into Joe Biden's presidency. The media outlet said it interviewed more than two dozen current and former U.S. officials, military contractors, social media analysts and academic researchers. 

The Reuters piece was confirmed by a senior U.S. Defense Department official, who acknowledged the U.S. military "engaged" in secret propaganda to disparage China's vaccine in the developing world. The official declined to provide details.

For Washington, China's offers of assistance to the developing world were perceived as having a growing influence on these countries, including the Philippines. While the U.S. prioritized itself in the COVID-19 vaccination process, its "Operation Warp Speed" plan forced developing countries to accept high prices, a medicine professor at Georgetown University who has worked with the World Health Organization told Reuters. 

"We didn't do a good job sharing vaccines with partners," another senior U.S. military officer directly involved in the campaign in Southeast Asia told Reuters. "So what was left to us was to throw shade on China's."

Spokespeople for Trump and Biden did not respond to requests for comment about the clandestine program.

The Chinese Foreign Ministry on Monday responded to the propaganda and denounced the U.S. for "spreading disinformation."

"Such practices by no means show the U.S. 'power' and only reveal its obsession with supremacy and hypocrisy. The international community needs to be clear-eyed about this," said Lin Jian, a spokesperson for the ministry.

(Cover: File photo of a researcher at China's Sinovac Biotech Ltd. /AFP)