ZF2001, trade-named Zifivax or ZF-UZ-VAC-2001, is an adjuvanted protein subunit COVID-19 vaccine developed by Anhui Zhifei Longcom in collaboration with the Institute of Microbiology at the Chinese Academy of Sciences.

[2][3] The vaccine candidate is in Phase III trials with 29,000 participants in China, Ecuador, Malaysia, Pakistan, and Uzbekistan.

[4][5] ZF2001 employs technology similar to other protein-based vaccines[6] in Phase III trials from Novavax, Vector Institute, and Medicago.

[18] In July, Longcom began a randomized, double-blind, placebo-controlled Phase II trial with 900 participants aged 18–59 in Changsha, Hunan divided into low-dose, high-dose, and placebo groups.

7 to 14 days after the administration of the third dose, the GMTs of neutralizing antibodies reached levels that were significantly higher than observed in human convalescent serum of recovering COVID-19 patients, especially in the 25 μg group.

[23][24] In December 2020, Ecuador's Minister of Health, Juan Carlos Zevallos announced Phase III trials would involve between 5,000 and 8,000 volunteers.

[32] On 7 September, the National Agency of Drug and Food Control of Indonesia (BPOM) published the emergency use authorization for Zifivax.

[33] On 10 January 2022, the National Agency of Drug and Food Control of Indonesia (BPOM) published the emergency use authorization for Zifivax as Booster for Sinovac.

The RBD-dimer significantly increases neutralizing antibodies compared to a conventional monomeric form and protected mice against MERS-CoV infection.