JOHANNESBURG, Sept 2 (Reuters) - South African insurer Discovery scrapped its annual dividend again on Thursday and said it may have to raise equity capital to cover costs linked to its investment in China's Ping An, sending its shares down 8%.

The company, which ties premium rates to its clients' lifestyles, has not paid a dividend since the COVID-19 pandemic took hold last year and said ongoing uncertainty over the impact of the virus meant it would continue to withhold payments for now.

Its growth-driving partnership with Ping An, meanwhile, would require 1.5 billion rand ($104 million) more capital from Discovery to meet regulatory requirements.

Chief Executive Adrian Gore said it would likely seek to fund this via an equity raise, not debt, with the proceeds ring-fenced for this purpose.

On dividends, he said the insurer had never been a big dividend payer, preferring to invest capital in growth, and there was still uncertainty around the impact of COVID-19.

"We don't believe as an insurer facing mortality claims we know fully the playout," he told Reuters in an interview, adding the restoration of dividends would be reviewed on an ongoing basis.

Discovery had already flagged a more than tenfold rise in headline earnings per share (HEPS) - the main profit measure in South Africa to 454.7 cents, compared to 45 cents a year earlier.

The main driver of the rise was the impact of changes in its economic assumptions. On a normalized basis its HEPS fell by 9% to 518.7 cents, compared to 570.7 cents last year.

Discovery also said it would make COVID-19 vaccination compulsory for its employees from January.

Gore said that employees who decline could be dismissed after a lengthy process to establish whether an accommodation needs to be made for, for instance, religious beliefs.

"If ... not, and you just don't believe in vaccines, then you can't work at Discovery," he said.

The insurer will also give vaccinated new clients better premiums. Existing members will be given incentives via its rewards program Vitality, which awards members points for desirable behavior that can get them benefits ranging from cheaper insurance to free coffees, Gore said. (Reporting by Emma Rumney; Editing by Wendell Roelf, Barbara Lewis and David Evans)