Japan may start administering third shots of coronavirus vaccines to people by the end of this year, the health ministry said Friday, as the nation looks to respond to the continued spread of the highly contagious Delta variant.

Health experts on a government subcommittee agreed on the necessity of the third shot and approved the ministry's plan to start inoculating people at least eight months after they received their second dose.

The potential booster shots may start being administered from November when the government aims to have completed vaccinating all eligible people who wish to be inoculated.

The Ministry of Health, Labor and Welfare said all three doses should be from the same manufacturer in principle, but it will look into more studies before drawing a conclusion.

As for the idea of giving people vaccines produced by different manufacturers, the ministry said the first and second shots should be doses of the same supplier, but it will revise rules to enable people to receive a booster vaccine produced by a different company under certain circumstances.

Three COVID-19 vaccines developed by Pfizer Inc., Moderna Inc. and AstraZeneca Plc are currently available in Japan, all of which are administered in two doses.

Israel is among the countries that have already started administering booster shots to their population.

The Japanese government will also discuss who will be eligible for the third shot and the order of priority, based on data and the progress of other nations.

A subcommittee member said medical workers treating COVID-19 patients need to be allowed to receive their third shot as soon as possible, while another member said the booster should not be rolled out until all those who currently want the vaccine have received both doses.

The vaccine makers have said third shots would be necessary to increase protection, with the number of breakthrough cases in which fully vaccinated people have contracted COVID-19 increasingly being reported in Japan and abroad.

Studies show that COVID-19 antibodies decrease six months after second shots have been administered and vaccine efficacy against the Delta variant becomes lower over time.