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Americans who received a single dose of the Johnson & Johnson Covid vaccine were better protected against serious illness and hospitalizations during the Omicron surge if they received a second dose of Pfizer-BioNTech or Moderna vaccines rather than an additional Johnson & Johnson vaccine. a new work It was released Tuesday by the Centers for Disease Control and Prevention.
The report does not offer a comparison with the protection afforded by two doses of mRNA vaccines and includes relatively few Johnson & Johnson recipients, making the findings difficult to interpret.
The findings broadly support the added benefit of a booster dose against the Omicron variant, which is known to partially suppress immune defense. However, the report is somewhat conflicting with other data It suggests that the single-dose Johnson & Johnson vaccine collected by the CDC prevents infections with the Omicron variant better than at least two doses of the mRNA vaccine.
These data suggest that people who receive a single dose of Johnson & Johnson vaccine are at a slightly higher risk of death than those who receive two doses of mRNA.
Separately, South African researchers discovered that two doses of the Johnson & Johnson vaccine provided protection against severe illness and hospitalizations comparable to that seen with two doses of the Pfizer-BioNTech vaccine.
CDC now recommends All adults who receive one or two doses of the Johnson & Johnson vaccine receive a booster dose of an mRNA vaccine. On Tuesday, the Food and Drug Administration a second booster has been authorized For all adults aged 50 and over, even those who have received three doses of mRNA (i.e. two plus a booster for the full vaccine).
In the new study, researchers analyzed data from 80,287 COVID-related visits and 25,244 hospitalizations to emergency departments or emergency care clinics in 10 states. Data were collected from December 16, 2021, when the Omicron variant was the dominant version of the virus, to March 7, 2022.
A single dose of the Johnson & Johnson vaccine had a 24 percent effectiveness in preventing emergency room and urgent care visits, compared to 54 percent after two doses of the vaccine.
The study found that the efficacy of combining a single dose of the Johnson & Johnson vaccine with the booster shot of an mRNA vaccine was similar to protection from three doses of mRNA. (This finding is consistent with results from other studies of booster shots.)
Vaccine efficacy against hospitalization showed a similar trend: 31 percent for a single dose of Johnson & Johnson, 67 percent for two doses of vaccine, 78 percent for one dose of Johnson & Johnson vaccine plus one mRNA vaccine, and 90 percent after three doses of mRNA vaccine.
However, margins of error for these estimates overlapped, meaning that the differences might not be significant.
The researchers noted that the study had other limitations. Data do not include data from two months after the last dose, on average. Other studies have suggested that the Johnson & Johnson vaccine performs better in the long term, while the efficacy of mRNA vaccines against infection declines sharply after the initial peak.
The study included less data on Johnson & Johnson recipients than those who received the mRNA vaccine, making the comparisons less reliable. For example, the researchers recorded 164 hospitalizations among people who received two doses of Johnson & Johnson vaccine, compared with nearly 8,000 among those who received three doses of mRNA.
And overall the numbers were too small to discriminate against vaccine recipients by age, sex, or presence of other health conditions, all of which may have skewed the results.
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