Stock prices of some South Korean biotechnology and pharmaceutical companies have increased based on expectations that China’s sudden spike in COVID-19 cases could positively impact their sales.

On early afternoon Wednesday, the stock price of in-vitro diagnostics company SD Biosensor’s stock price went up 5.9 percent to 29,600 won ($23.24). Seegene, another major in-vitro diagnostics company, saw its stock price climb 6.5 percent to 27,800 won.

Their stock price hikes came after the South Korean government's recent decision to resume COVID-19 testing for arrivals from China. The government said all travelers from China will be required to present a negative result from a polymerase chain reaction test taken within 48 hours of departure, or 24 hours for a rapid antigen test. They also have to take another PCR test within one day of arrival.

The decision came amid an increasing number of COVID-19 infections in China. The government said Wednesday that around 31 percent of all new infections that came from abroad were from China.

Whether South Korean test kit makers’ exports of test kits will immediately improve, however, remains uncertain.

An industry source said, “an increasing number of infections does not immediately lead to an increase in demand for test kits, as governments usually keep a certain amount of them in stock.”

Another source added that demand for test kits may not stay high long enough to impact sales, as the latest COVID-19 outbreak in China may start to recede starting in end-January.

China has also not been a lucrative destination for Korean test kit makers.

According to Korea Customs Service data, exports of COVID-19 test kits to China last year only reached $44 million, accounting for only 1.3 percent of all test kits exports, which reached $3.24 billion.

However, the stock prices of Korean companies that operate offices in China are expected to see some increased sales.

Boditech Med, a Korean diagnostics manufacturer which operates its offices in China, said the company expects sales increases this year based on recently increased demand for diagnostics products.

Beijing Hanmi Pharmaceutical is also expected to see improvement in sales performance, as demand for cold medicines are expected to go up. An official from Hanmi Pharmaceutical said the company has secured additional production capacity to meet increasing demand for cold medicines in China.