Federal health officials are strongly recommending that any American who is pregnant, planning to become pregnant or currently breastfeeding get vaccinated against the coronavirus as soon as possible.

COVID-19 poses a severe risk during pregnancy, when an individual’s immune system is lower, and raises the risk of stillbirth or another poor outcome, the Centers for Disease Control and Prevention said.

Twenty-two pregnant women died of COVID-19 in August, the highest number in a single month since the pandemic started.

Some 125,000 pregnant people have tested positive for the virus; 22,000 pregnant individuals with COVID-19 have been hospitalized, and 161 have died. Hospital data indicates that 97% of those who were infected with the virus when they were hospitalized — for illness, or for labor and delivery — were not vaccinated.

Vaccination rates among those who are pregnant are lower than among the general population. Fewer than one-third of all pregnant women were vaccinated before or during their pregnancy, the agency said this week. The rates vary widely by race and ethnicity, with the highest vaccination coverage among pregnant Asian American individuals, nearly half of whom are vaccinated, and the lowest rates among pregnant Black individuals, at just 15%.

Pregnancy is on the CDC’s list of health conditions that increase the risk of severe COVID-19. Although the absolute risk of severe disease is low, pregnant patients who are symptomatic are more than twice as likely as other symptomatic patients to require admission to intensive care or interventions like mechanical ventilation, and may be more likely to die.