World Rugby announced on Friday this year's sevens tournaments in Singapore and Cape Town have been cancelled due to Covid-19 travel restrictions.
Events in Vancouver on September 18-19 and Edmonton a week later, for men and women, will be the only competitions on this season's circuit.
"The truly global nature of the Series has made it difficult to plan with certainty in this uniquely challenging time as the ongoing and dynamic impacts and travel restrictions associated with the COVID-19 pandemic continue to present a challenge to all stakeholders," World Rugby chief executive Alain Gilpin said in a statement.
"Together with the host organisers we are disappointed not to be able to deliver the planned Series events in Singapore and Cape Town this year, however we look forward to bringing the joy and spirit of rugby sevens back to both cities in 2022," he added.
Next year's series will start on the weekend of this November 26-27 in Dubai with a second event a week later in the same city.
Tournaments in Sydney and Hamilton in New Zealand will not be part of the campaign due to the coronavirus pandemic.
"The complete HSBC World Rugby Sevens Series 2022 schedule will be announced later this month," sport's govrning body said.
"Rugby sevens players and fans can look forward to a very busy and exciting year in 2022 with the Series followed by the Commonwealth Games in Birmingham on 29-31 July and concluding with the Rugby World Cup Sevens in Cape Town on 9-11 September," it added.