Speculation, but

UNICEF and the Ministry of Health had initially aimed to vaccinate 20 percent of the Haitian population by May, or roughly 2.5 million of the most vulnerable people, including healthcare workers and teachers. But that plan fell apart when the country rejected COVAX’s first AstraZeneca shipment.

The Haitian government refused that initial shipment, citing concerns over adverse side effects like blood clotting associated with the AstraZeneca brand.

According to the World Health Organization, Haiti is one of a handful of countries that have not begun vaccination programmes.

Haiti is among the low- and lower middle-income countries targeted by a donation of 55 million Pfizer doses from US President Joe Biden’s administration, but it’s unclear when Haiti will receive its first delivery.

“We’re hoping for sometime in July,”

https://www.thenewhumanitarian.org/news/2021/7/5/haiti-still-awaiting-first-covid-vaccines-as-cases-surge