Washington, Apr 26 (IANS): An increasing number of Americans have missed their second dose of Covid-19 vaccine, according to data from the US Centers for Disease Control and Prevention.

Nearly 8 per cent of Americans have missed the second dose -- up from about 3.4 per cent in March, the CNN reported on Sunday. However, it's not an exact count, the report stated.

"If a person received the two doses from different reporting entities, those two doses may not have been linked together," a CDC spokesperson was quoted as saying to CNN.

"For example, if a person received their first dose at a clinic run by the state, and second dose from a tribal health clinic, they might not be linked and it could look like they missed the second dose," the spokesperson said.

Moreover, Americans missing second doses was expected, the report quoted CDC as saying. Groups initially prioritised for vaccination, such as health care workers, were more likely to get vaccinated at their work site, "potentially reducing barriers and increasing adherence to the recommended vaccine schedule", a spokesperson said."

The reasons behind the delayed or missed second doses, however, require further analysis," the spokesperson said, and officials should work to understand whether this is due to access or vaccine hesitancy.

Nearly 229 million doses of Covid-19 vaccines have been administered in the US, according to CDC data published Sunday. About 3 million more administered doses were reported since Saturday, putting the seven-day average of administered doses at about 2.8 million doses per day. The numbers show a slight drop from earlier in the month, when the average pace of new doses administered peaked at 3.4 million shots per day on April 13.

The recent pause on the Johnson & Johnson Covid-19 vaccine had contributed to the decline, CDC's Dr Amanda Cohn was quoted as saying to CNN.