ISLAMABAD — Pakistani Prime Minister Imran Khan has tested positive for the coronavirus two days after he received his first vaccine dose, officials announced Saturday.

Dr. Faisal Sultan, Khans special assistant on health, said the prime minister has quarantined himself at his private home on a hilltop in an Islamabad suburb. The government tweeted a statement from Sultan saying the vaccine had not been effective because Khan had received it so recently, and it was only the first of two required doses.

There has been a spike in COVID-19 cases in the capital and in eastern and northern Pakistan, where authorities on Saturday reported daily totals of 42 new deaths and 3,876 new coronavirus infections. Overall, the virus has killed close to 14,000 people in Pakistan and infected more than 623,000.

The positivity rate in Pakistan has jumped to over 8%, prompting government officials to say people could face a lockdown-like situation if violations of social distancing guidelines continued.

Since February, Pakistan has been using a coronavirus vaccine donated by neighboring China. Health workers have been vaccinated and now older people are receiving the jab.

Media reports say a private Pakistani pharmaceutical company has imported 50,000 doses of the Russian Sputnik V vaccine, but it was unclear at what price the vaccine will be available to people.