A person looks through a door into a closed community vaccination center administering the BioNTech vaccine imported by Fosun Pharma in Hong Kong, on March 24, 2021. (PHOTO/BLOOMBERG)

Initial investigations by German drugmaker BioNTech and its regional distributor found no safety concerns with batches of vaccines sent to Hong Kong, after packaging defects prompted a halt in the use of the COVID-19 vaccine in the city.

READ MORE: HK, Macao suspend BioNTech vaccines over packaging defect

Early findings did not rule out the possibility that packaging defects may have been because of environmental factors during long-haul transport, the Hong Kong government said in a statement. The government, BioNTech and Shanghai Fosun Pharmaceutical Group Co aim to conclude the investigation within a week, it said.

Early findings did not rule out the possibility that packaging defects may have been because of environmental factors during long-haul transport, the Hong Kong government said in a statement

Hong Kong, along with neighboring Macao, announced on Wednesday the temporary suspension of the shots because of packaging defects. 

The defects, which included loose vial caps and stained bottles, affected about 1.3 million doses that were delivered to the financial hub. About 150,000 people had received BioNTech shots in Hong Kong prior to the halt.

Fosun and BioNTech have studied the entire supply chain, including the sealing process in BioNTech’s German facilities, vaccine packaging, transport to Hong Kong, logistical processing and storage after their arrival in the city, as well as inspections at community vaccination centers. They found no “obvious systematic factors” that could have led to the defects from packaging to usage, according to the statement.

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The companies also said that they did not believe the defects were the results of cold chain and logistic management issues. Random testing of remaining vaccine vials with intact packaging did not find evidence of leakage.