Europe Delays Fourth COVID-19 Vaccine Dose for Population Under 80, Contrary to U.S. Approach

Compiled by Fan Dongdong

Last week, the U.S. government signed an executive order to start administering the fourth dose (i.e., the second booster shot) of the COVID-19 vaccine for Americans aged 50 and above. However, the European drug regulatory agency and vaccine expert advisors recently expressed opposing views, stating that it might be premature to administer a fourth dose of Pfizer or Moderna's mRNA COVID-19 vaccines in the general population at this stage.

In response, European regulatory authorities stated that it is necessary to review real-world data regarding the higher risk of Covid-19 infection in this age group and the protective efficacy of a fourth vaccine dose. The European Centre for Disease Prevention and Control (ECDC) and the European Medicines Agency (EMA) clearly pointed out that there is currently no conclusive real-world evidence within the EU. Moreover, among adults aged 60-79 with normal immune systems, the vaccine's protection against severe disease significantly diminishes. Therefore, at this stage, there is no clear evidence to support the immediate administration of a fourth dose of the Covid-19 vaccine.

As of the end of March 2022, EU authorities reported that 83% of European adults had completed their primary vaccination series, and 64% of adults had received a booster shot. European regulators stated they will continue to monitor relevant data, and if new signals emerge, it may be necessary in the future to consider a fourth dose for that age group. However, for individuals under 60, EU agencies indicated that there is "currently no conclusive evidence that vaccine protection against severe disease is waning" for those with normal immune systems, nor is there confirmed evidence supporting the need for a fourth dose.

The European Centre for Disease Prevention and Control (ECDC) and the European Medicines Agency (EMA) emphasized in a statement that evidence regarding the protective effectiveness of a fourth dose of the COVID-19 vaccine mainly comes from Israel. Local trial data indicates that administering a second booster at least four months after the first booster can restore antibody levels without causing any additional safety concerns. Relevant trial data also suggests that the second booster can indeed provide extra protection against severe illness. However, it is important to note that the duration of this preventive effect remains unclear, and evidence on the level of protection offered is still quite limited.

Meanwhile, the US FDA Vaccines and Related Biological Products Advisory Committee (VRBPAC) has already met to discuss the US Covid-19 booster vaccination plan. However, if the clinical trials of Moderna and Pfizer’s mRNA vaccines targeting the Omicron variant BA.2 do not complete by early May this year, there will likely be insufficient vaccines to meet the practical needs of the US government's plan to administer a fourth dose in the fall.

Reference Source: Europe Holds Off on a Fourth Covid Vaccine Shot for Those Under the Age of 80