Covid Vaccines Did Not Protect Adolescents as Effectively During the Omicron Surge

Researchers reported on Wednesday that Covid vaccines reduced protection against hospitalization among children 12 and older during the latest Omicron surge.

The vaccine's effectiveness against hospitalization remained the same for children aged 5 to 11 years, and for adolescents ages 12 to 18 years.

The effectiveness against hospitalization for less severe illness went down among these children. The New England Journal of Medicine published the findings.

The data is consistent with studies that show that the Omicron variant of the vaccine still prevented death and severe illness in all age groups.

The vaccine still protects children from the worst outcomes of infections, even if they are hospitalized, according to a study led by a researcher at the Centers for Disease Control and Prevention.

Most of the adolescents in the study had at least one underlying condition, and 93 percent of them were unvaccinated.

Only a small percentage of children and adolescents in the United States are fully protected from vaccine-related diseases. The percentages have not budged in the past few months.

The retreat of the coronaviruses is complicating the decision for some parents. Cases and deaths have fallen to their lowest levels in a year, but no one knows if the BA.2 subvariant of Omicron will bring another wave.

Some parents think their children's risk of Covid is trivial, so they have been reluctant to give them the vaccine. More children were hospitalized during the Omicron surge than at any other time in the Pandemic, but they are less likely to become seriously ill than adults.

The researchers analyzed medical records and interviewed parents of children who were hospitalized for Covid. Children who tested positive for the coronaviruses but were admitted to the hospital for other reasons were excluded.

The researchers were able to identify 1,185 children who had Covid, compared to 1,627 who did not. Among those who were hospitalized for Covid, 291 received life support and 14 died.

The data from 31 hospitals in 23 states was included in the study. Up to 44 weeks after immunization, the effectiveness against hospitalization was more than 90 percent among adolescents.

During the Omicron surge, the protection against hospitalization dropped to about 40 percent, regardless of the time since vaccination.

The vaccine effectiveness against critical illness among hospitalized adolescents remained high at 81 percent, but had fallen to 20 percent for less severe illness.

The new study looks at vaccine effectiveness in relation to severity of illness among hospitalized patients. It is possible that this trend would appear among adult patients if they were analyzed the same way.

He said that the split along critical and noncritical is interesting.

In children ages 5 to 11 years, full vaccination had an effectiveness of over 70 percent. The data was gathered during the Omicron surge because these children became eligible for vaccine. There was not enough to analyze effectiveness by severity of illness.

A majority of adolescents and younger children in the study had at least one underlying medical condition, like asthma.

Dr. Luciana Borio is a former acting chief scientist at the Food and Drug Administration.

She said that it shows the importance of vaccines for children 5 and older.

She and others said that the vaccines did not do as well against the Delta variant because the Omicron variant can partly dodge immune defenses. Two doses of the vaccine offered no defense against moderate illness caused by the Omicron variant in adolescents, according to a recent study. Boosters are now recommended for all Americans over the age of 12.

The wide range of symptoms for which children were hospitalized may be the reason for the large discrepancy in vaccine effectiveness between those who needed life support and those who did not. One in four adolescents in the study required life-supporting interventions.

Most children who were hospitalized during the Omicron surge recovered quickly, according to a doctor who was not involved in the study.

She said that the children who were admitted were either very sick, or they were mostly admitted because they had low oxygen saturation.

Parents were more likely to bring young children to the hospital during the Omicron surge.

The decline in vaccine protection among adolescents may have been caused by waning effectiveness over time because too much time had elapsed since their immunizations, according to some researchers.

The vaccine effectiveness against the Omicron variant was found to be 43 percent up to 22 weeks after immunization, and 38 percent between 23 and 44 weeks. Waning immunity seemed to be less of a factor than the variant itself.

It looked like it was related to Omicron.

The adolescents in the new study only received two doses of the vaccine. A previous study suggested that a booster shot improves protection against moderate illness in this age group, as it does in adults.

Akiko Iwasaki, an immunologist at Yale University, believes that children should get three doses. Fourteen percent of children 12 and older have received a booster dose.