Tissue-cultured smallpox vaccine appears promising

March 10, 2009

Administration of a tissue-cultured smallpox vaccine showed signs of an effective vaccine response with no serious adverse events, according to a study in the March 11 issue of JAMA.

"The threat of smallpox bioterrorism has prompted reconsideration of the need for smallpox vaccination. Serious adverse events associated with first-generation vaccines such as the New York City Board of Health (Dryvax), Lister, and Ikeda strains have raised obstacles to vaccination campaigns in the United States," the authors write. They add that certain second-generation vaccines are also often accompanied by a high frequency of adverse events. "Developing a vaccine that is safer than first-generation vaccines yet highly immunogenic [producing immunity or an immune response] is crucial to constructing a prevention plan in the event of bioterrorist attack."

Tomoya Saito, M.D., Ph.D., of Keio University, Tokyo, and colleagues examined the clinical and immunological responses to the LC16m8 vaccine in adults who had been previously vaccinated (n = 1,692) and in those who had not (n = 1,529). LC16m8 is a live, attenuated (reduced in strength), tissue-cultured third-generation vaccine that was administered to more than 100,000 infants in Japan between 1973 and the beginning of 1976. The adults in this study, who are in the Japan Self-Defense Forces, received the LC16m8 vaccine between 2002 and 2005. Vaccinees were examined 10 to 14 days after vaccination to determine if they had developed a major skin reaction ("take"; a measure of immune response). The researchers monitored vaccinees for adverse events for 30 days after the vaccination.

The researchers found that administration of the vaccine was associated with high levels of seroconversion (development of antibodies) in adults who were not previously vaccinated and yielded an effective booster response in some previously vaccinated individuals. Seroconversion or an effective booster response among the individuals with take was elicited in 37 of 41 (90.2 percent) participants who had not been vaccinated before and in 93 of 155 (60.0 percent) previously vaccinated participants. The overall proportion of clinical take was significantly higher in primary vaccinees (1,443/1,529 [94.4 percent]) than in revaccinees (1,465/1,692 [86.6 percent]).

"Appropriate training in vaccination technique may help achieve a higher proportion of takes, because we observed a higher proportion of takes in later vaccination rounds," the authors write.

One case of allergic dermatitis and another of erythema multiforme (a rash), both of which were mild, were suspected to be caused by vaccination. No severe adverse events were observed.

"We demonstrated the immunogenicity of LC16m8 vaccine in vaccinia-naive adults by a single vaccination. LC16m8 vaccine also induces a good booster response in previously vaccinated individuals. Our study also offers supportive evidence for the safety of LC16m8 vaccine in adults; LC16m8 vaccine appears to be a viable alternative to first-, second- and other third-generation vaccines in a smallpox preparedness program," the researchers conclude.
-end-
(JAMA. 2009;301[10]:1025-1033. Available pre-embargo to the media at www.jamamedia.org)

Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

For More Information: Contact the JAMA/Archives Media Relations Department at 312-464-JAMA or email: mediarelations@jama-archives.org.

The JAMA Network Journals

Related Immune Response Articles from Brightsurf:

Boosting chickens' own immune response could curb disease
Broiler chicken producers the world over are all too familiar with coccidiosis, a parasite-borne intestinal disease that stalls growth and winnows flocks.

Cells sacrifice themselves to boost immune response to viruses
Whether flu or coronavirus, it can take several days for the body to ramp up an effective response to a viral infection.

Children's immune response more effective against COVID-19
Children and adults exhibit distinct immune system responses to infection by the virus that causes COVID-19, a finding that helps explain why COVID-19 outcomes tend to be much worse in adults, researchers from Yale and Albert Einstein College of Medicine report Sept.

Which immune response could cause a vaccine against COVID-19?
Immune reactions caused by vaccination can help protect the organism, or sometimes may aggravate the condition.

Obesity may alter immune system response to COVID-19
Obesity may cause a hyperactive immune system response to COVID-19 infection that makes it difficult to fight off the virus, according to a new manuscript published in the Endocrine Society's journal, Endocrinology.

Immune response to Sars-Cov-2 following organ transplantation
Even patients with suppressed immune systems can achieve a strong immune response to Sars-Cov-2.

'Relaxed' T cells critical to immune response
Rice University researchers model the role of relaxation time as T cells bind to invaders or imposters, and how their ability to differentiate between the two triggers the body's immune system.

A novel mechanism that triggers a cellular immune response
Researchers at Baylor College of Medicine present comprehensive evidence that supports a novel trigger for a cell-mediated response and propose a mechanism for its action.

Platelets exacerbate immune response
Platelets not only play a key role in blood clotting, but can also significantly intensify inflammatory processes.

How to boost immune response to vaccines in older people
Identifying interventions that improve vaccine efficacy in older persons is vital to deliver healthy ageing for an ageing population.

Read More: Immune Response News and Immune Response Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.