Vaccine description | |
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Target | SARS-CoV-2 |
Vaccine type | Protein subunit |
Clinical data | |
Trade names | Zifivax |
Routes of administration | Intramuscular |
ATC code |
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Legal status | |
Legal status | |
Identifiers | |
DrugBank |
Part of a series on the |
COVID-19 pandemic |
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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. [1] [2] The vaccine candidate is in Phase III trials with 29,000 participants in China, Ecuador, Malaysia, Pakistan, and Uzbekistan. [3] [4]
ZF2001 employs technology similar to other protein-based vaccines [5] in Phase III trials from Novavax, Vector Institute, and Medicago. [6]
ZF2001 was first approved for use in Uzbekistan and later China. [7] [8] Production capacity is expected to be one billion doses a year in China [9] and 200 million in Uzbekistan. [10] By July, 100 million doses had been administered in China and Uzbekistan. [11]
It is administered in three doses over a period of two months. [9]
In August 2021, preliminary data from a phase III study with 28,500 participants indicated an overall efficacy of 82% against disease of any severity. Efficacy was 93% against the Alpha variant and 78% against the Delta variant. [12] [13]
In July 2021, lab studies showed ZF2001 retained neutralizing effects against B.1.429 ( Epsilon), B.1.351( Beta), P.1( Gamma), B.1.525( Eta), B.1.617.1( Kappa), the neutralizing titers decreased ranging from 1.1 fold to 2.1 fold, but the neutralizing efficacy were still good. [14]
According to industry experts, production for this kind of vaccine is stable and reliable, and easier to achieve large-scale industrial production at home and overseas. However it was noted it can be very inconvenient for people to come back for a second and third dose. [9] Subunit vaccines are delivered alongside adjuvants and booster doses may be required. [15]
The company's vaccine manufacturing facility was put into use in September. [16] In February 2021, management said the company had an annual production capacity of 1 billion doses. [9]
In July 2021, an agreement was reached to produce the vaccine in Uzbekistan starting with 10 million doses a month and eventually 200 million doses a year. [10]
In June 2020, Longcom began a double-blind, randomized, placebo parallel controlled Phase I trial with 50 participants aged 18–59 in Chongqing divided into low-dose, high-dose, and placebo groups. [17]
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. [18] In August, an additional Phase II trial was launched with 50 participants aged 60 and above. [19] [1]
In Phase II results published in The Lancet, on the two-dose schedule, seroconversion rates of neutralizing antibodies after the second dose were 76% (114 of 150 participants) in a 25 μg group and 72% (108 of 150) in a 50 μg group. On the three-dose schedule, seroconversion rate of neutralizing antibodies after the third dose were 97% (143 of 148 participants) in the 25 μg group and 93% (138 of 148) in the 50 μg group. 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. [20]
In December 2020, Longcom began enrollment of a Phase III randomized, double-blind, placebo-controlled clinical trial for 29,000 participants, including 750 participants between 18-59 and 250 participants 60 and older in China and 21,000 participants between 18-59 and 7,000 participants 60 and older outside China. [21] [16]
In December 2020, Malaysia's MyEG announced it would conduct Phase III trials. If the trials were successful, MyEG would be the sole distributor of ZF2001 in Malaysia for 3 years. [4]
In December 2020, Uzbekistan began a year-long Phase III trial of ZF2001 with 5,000 volunteers between 18 and 59. [22] [23]
In December 2020, Ecuador's Minister of Health, Juan Carlos Zevallos announced Phase III trials would involve between 5,000 and 8,000 volunteers. [24]
In February 2021, Pakistan's Drug Regulatory Authority (DRAP) approved Phase III trials with approximately 10,000 participants to be conducted at UHS Lahore, National Defense Hospital, and Agha Khan Hospital. [25]
The vaccine is also being trialed in Indonesia. [13]
In July 2021, Longcom began a randomized, blinded, placebo-controlled phase I with 75 participants aged 3–17. [26] [27]
In November 2021, Longcom began a phase II with 400 participants aged 3–17. [28]
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On 1 March 2021, Uzbekistan granted approval for ZF2001 (under tradename ZF-UZ-VAC 2001) after having taken part in the Phase III trials. [8] In March, Uzbekistan received 1 million doses and started vaccinations in April. [29] By June, a total of 6.5 million doses had been delivered. [30]
In March 2021, China approved of ZF2001 for emergency use after being approved by Uzbekistan earlier in the month. [7]
In June 2021, Malaysia's MyEG signed a letter of intent to purchase 10 million doses of the vaccine. [31]
On 7 September, the National Agency of Drug and Food Control of Indonesia (BPOM) published the emergency use authorization for Zifivax. [32]
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. [33]
As described in Cell, the CoV spike receptor-binding domain (RBD) is an attractive vaccine target for coronaviruses but is constrained by limited immunogenicity, however a dimeric form of MERS-CoV RBD offers greater protection. The RBD-dimer significantly increases neutralizing antibodies compared to a conventional monomeric form and protected mice against MERS-CoV infection. CoV RBD-dimer have been produced at high yields in pilot scale production. [34]
Rather than injecting a whole virus, subunit vaccines contains virus particles specially selected to stimulate an immune response. Because the fragments cannot cause disease, subunit vaccines are considered very safe. [15] Subunit vaccines in widespread use include the Hepatitis B vaccine and Pertussis vaccine. However, as only a few viral components are included in the vaccine which does not display the full complexity of the virus, their efficacy may be limited. [35]