Nairobi: Over the course of the pandemic he has expressed wariness about foreign-made goods, including COVID-19 vaccines.
The president's comments came days after the country of some 60 million people mourned the death of one of its highest-profile politicians, the vice president of the semi-autonomous island region of Zanzibar, whose political party had earlier said he had COVID-19.
The president's chief secretary also died in recent days, though the cause was not revealed.
Magufuli, speaking at the chief secretary's funeral in a nationally televised broadcast on Friday, urged the nation to participate in three days of prayer for unspecified "respiratory" illnesses that had become a challenge in the country.
Tanzania has not updated its number of coronavirus infections since April as the president has insisted COVID-19 had been defeated.
Tanzania's official number of coronavirus infections remains at just 509, but residents report that many people have become ill with breathing difficulties and hospitals have seen a rise in patients for "pneumonia."
The director-general of the World Health Organization, Tedros Adhanom Ghebreyesus, has added his voice to growing calls for Tanzania to acknowledge COVID-19 for the good of its citizens, neighbouring countries, and the world, especially after a number of countries reported that visitors arriving from Tanzania tested positive for the virus.
Tedros in a statement on Saturday called Tanzania's situation "very concerning" and urged Magufuli's government to take "robust action." Others recently expressing concern include the United States and the local Catholic church.
—IANS