China Recommends Homologous Boosters for COVID-19 Vaccines, Discourages Mixing

　　 【Official Release】

Currently, the overseas pandemic continues to spread, and coupled with seasonal factors, the risk of transmission and spread is elevated. At a press conference held on October 24 by the Joint Prevention and Control Mechanism of the State Council, Mi Feng, spokesperson for the National Health Commission, stated that since October 17, scattered local outbreaks have emerged in China, developing rapidly. Within a week, the outbreak has affected 11 provinces, and the risk of further transmission continues to increase.

　　The source of the outbreak is still under epidemiological investigation and source tracing.

Wu Liangyou, Deputy Director of the Bureau of Disease Prevention and Control under the National Health Commission, stated: "Regarding the source of the outbreak, epidemiological investigation and source tracing are currently still underway. Based on the results of epidemiological investigations and viral sequencing, the complete viral genome sequence from the cases shows low homology with that of previous domestic outbreaks in China, indicating that this outbreak is caused by a new overseas imported source."

Wu Liangyou stated that the current outbreak exhibits two key characteristics: first, it has a wide geographic spread, with the vast majority of cross-regional cases identified to date linked to tour groups or self-driving travel; the high inter-regional mobility of individuals at potential risk, coupled with the involvement of multiple provinces, poses a risk of further epidemic expansion. Second, it is highly transmissible. The virus responsible for this outbreak is the Delta variant. The high viral nucleic acid load detected in the respiratory samples of some cases indicates substantial viral shedding and strong infectivity, resulting in a high risk of secondary transmission among exposed populations. It is anticipated that as the investigation and screening of at-risk populations continue, the number of newly identified cases will likely increase over the coming days. The geographic scope of the outbreak may further expand.

　　Four types of vaccines are eligible for booster doses, but mixing and matching is not currently recommended.

Wu Liangyou stated that implementing booster vaccination is of great significance for protecting susceptible populations and effectively curbing the spread of the epidemic. Internationally, some countries have already initiated or announced booster vaccination programs.

Based on expert research and evaluation and the needs of epidemic prevention and control, the Joint Prevention and Control Mechanism of the State Council has recently launched a COVID-19 vaccine booster vaccination program. Individuals aged 18 and above who have completed their full primary vaccination series at least six months prior are eligible to receive a single booster dose of the inactivated vaccines manufactured by Beijing Institute of Biological Products (Sinopharm CNBG), Beijing Sinovac Biotech, and Wuhan Institute of Biological Products (Sinopharm CNBG), as well as the adenovirus vector vaccine manufactured by Tianjin CanSino Biologics.

“Regarding booster vaccination, experts recommend using homologous vaccines, meaning vaccines based on the same technological platform.” Wang Huaqing, Chief Expert of the Immunization Program at the Chinese Center for Disease Control and Prevention, pointed out that China’s current booster vaccination strategy is homologous vaccination, and mixed vaccination is not recommended.

The expert panel recommends that priority populations, including certain personnel working at customs, border inspection, aviation, quarantine facilities, and designated hospitals, individuals studying abroad, immunocompromised persons (including those with immune deficiencies), and adults aged 60 and above, may consider receiving a booster dose six months after completing the primary vaccination series.

　　Whether further vaccination is required after the third dose remains under discussion.

Studies indicate that as time passes following vaccination, neutralizing antibody levels in some individuals decline. Given that vaccine-induced immunity wanes, is it necessary to receive a fourth or fifth dose after the third shot?

“Continuously boosting immunity and repeatedly administering booster doses is not our ultimate choice,” Wang Huaqing stated. An ideal vaccine should achieve robust efficacy upon completion of the primary immunization series. Even if subsequent boosters are required, the number of booster doses will be limited.

“We hope that in the future there will be better vaccines and improved vaccination schedules to achieve robust population-level protection,” Wang Huaqing said.

　　It is recommended that the interval between the administration of the influenza vaccine and the COVID-19 vaccine be at least 14 days.

Surveillance results indicate that since March 2021, influenza activity in China has been higher than during the same period last year. Particularly since September, influenza activity in some southern provinces has shown a significant upward trend.

“Based on a comprehensive assessment by experts, there may be a risk of an influenza epidemic this winter and next spring. If the COVID-19 epidemic resurges, a compounded risk may arise,” Wang Huaqing pointed out.

He stated that the Technical Guidelines for COVID-19 Vaccination recommend an interval of at least 14 days between the administration of the influenza vaccine and the COVID-19 vaccine. (Reporter: Jin Zhenya; Correspondent: Cao Yue)