The pandemic dealt a serious setback to global efforts to immunize children against diseases like measles and polio, the Centers for Disease Control and Prevention reported on Thursday, reducing worldwide coverage for some vaccines to levels not seen since more than a decade ago.
The proportion of eligible children who received a polio vaccine fell to 83 percent in 2020 from 86 percent the year before, as did coverage with the third dose of the diphtheria-tetanus-pertussis vaccine, known as DTP3. Coverage with the measles vaccine also dipped slightly, to 84 percent last year from 86 percent in 2019.
Those setbacks, while seemingly small, meant that millions more children missed out on routine immunizations during the pandemic, putting them and their communities at risk.
Globally, nearly 23 million children targeted for the DTP3 shot were not vaccinated in 2020, compared with 19 million in 2019, the C.D.C. said. The vast majority of those had not received a single dose of diphtheria-tetanus-pertussis vaccine. Not since 2009 had coverage with that vaccine been so low.
The C.D.C. scientists involved in the report called for action to be taken to address the immunity gaps of preventable diseases in countries already saddled with Covid outbreaks. Scientists from the World Health Organization and UNICEF also were co-authors on the study.
The decline in vaccinations follows a decade of stagnant immunization levels. In 2019, measles deaths swelled to their highest levels in 23 years, a consequence of what public health experts described as insufficient vaccination coverage. Scientists said that the pandemic had hampered the tracking of measles outbreaks.
The pandemic also disrupted immunization programs, the C.D.C. report said, interrupting the supply of basic vaccines and making it more difficult to administer them.
Immunization levels for diphtheria-tetanus-pertussis and measles were lowest in much of Africa, the report said. The W.H.O. also said on Thursday that only five of Africa’s 54 nations were expected to reach a year-end goal of vaccinating 40 percent of their people against Covid. UNICEF, a United Nations agency working to distribute coronavirus vaccines, warned of a shortfall next year in syringes for both Covid and routine vaccinations.