United States: why millions of vaccinees skip the second dose

Millions of Americans they don’t get their second dose of the Covid-19 vaccine, and the number is increasing.

More than 5 million people, or almost 8% of those who received the first dose of the vaccine of Pfizer or Moderna, they skipped the second dose, according to the most recent data from Centers for Disease Control and Prevention (CDC). And this percentage is more than double among those who were vaccinated in the first weeks of the national vaccination campaign.

As the country grapples with the problem of millions of Americans who do not want to be vaccinated directly, local health authorities face the unforeseen challenge of ensuring that those who are vaccinated receive the full immunization schedule.

The reasons for absenteeism for the second dose are varied. When consulted, people argue fear of side effects, like flu symptoms, and others say they feel sufficiently protected with just one dose.

These reactions were predictable, but there is another unexpected and widespread obstacle: many inoculation centers have canceled the application changes of the second dose because they remained no supplies O due to lack of correct dose in their stocks.

The pharmacy chain Walgreens, one of the largest vaccine administrators in the United States, has given many people who had received a first dose of Pfizer, for example, in places that only had Moderna vaccine, or vice versa.

Several Walgreens customers report that pharmacy staff had to help them find another store in the chain that had the correct vaccine, sometimes without much success. And it can be assumed that many more gave up halfway.

Experts knew early on that it would be difficult to get everyone vaccinated with the first dose to show up three and four weeks later for the second. It was therefore to be expected that as the vaccination progresses, the number of those avoiding the second dose will also increase.

But authorities in some states say the trend is alarming anyway and are trying to find a way around the problem so that the percentage of “half-vaccinated” does not skyrocket.

There is growing evidence, both from clinical trials and real-world vaccination campaigns, of the Dangers of skipping the second dose. Compared to the two-dose regimen, a single injection triggers a weaker immune response and may make recipients more susceptible to more dangerous variants of the virus. And if a single dose allows partial immunization against Covid, no one knows how long this half-protection lasts.

“It is very worrying, because the second dose is necessary”, explains the doctor. Paul Offit, Professor at the University of Pennsylvania and member of the US Food and Drug Administration (FDA) Vaccine Advisory Board.

The risk is great because in the United States there is only one licensed single-dose vaccine, that of Johnson & Johnson, Its application was specifically suspended last month, when it was linked to a very rare but serious side effect related to blood clotting. Federal health officials gave the green light to resume application of this vaccine on Friday, but it is likely that a combination of fear of people and problems current production make Johnson’s vaccine an increasingly less viable option for many people.

The CDC’s count of second missed doses is up to April 9 and only includes people who received a first dose of Moderna before March 7 or a first dose of Pfizer before March 14.

Although millions of people did not attend the second request, overall compliance rates, with 92% of people receiving the full plan, are up to historical standards. In the case of the vaccine that protects against shingles, for example, nearly three-quarters of adults return for their second dose.

In some cases, absenteeism may be due to shift problems or missed second dose. Some vaccination sites have had to cancel shifts because they did not receive the expected vaccines. There are also people who say they canceled their appointment for the second dose, or attended, but there were no available doses of the brand to apply.

Some people have flexible hours and a shift change doesn’t affect them, but it’s more difficult for those who don’t have direct access to transportation or who have strict work schedules, he says. . Elena cyrus, epidemiologist and infectious disease specialist at the University of Central Florida.

Walgreens gave some customers a second dose change in locations that did not have the same vaccine they received in their initial dose. The company assures that this problem was resolved at the end of March.

Susan ruelThe 67-year-old man was scheduled to receive his two doses of the vaccine at various Walgreens sites in Manhattan. Ruel says he received his first dose of Pfizer in February and with no issues, but when he arrived for his second application, they told him only the dose of Moderna was in stock there.

One of the pharmacists at that branch told him that about 30 blocks away there was another Walgreens store where they had a supply of Pfizer vaccine. But while she was waiting for the subway to go to the other place, they called her on the phone to let her know that she was also running out of doses of Pfizer.

The next day, Ruel finally managed to get the second dose at a third Walgreens location, but says many more would have given up instead. “He does it with the least inconvenience,” he says.

The CDC says there is little data on vaccine effectiveness when more than 6 weeks elapse between the first and second dose, but some countries, such as Great Britain and Canada, apply them 3 to 4 months apart.

Translation of Jaime Arrambide

The New York Times

Conocé The Trust Project