Fractional dose of scarce meningitis vaccine may be effective in outbreak control

Dec 02, 2008

A partial dose of a commonly used vaccine against meningitis may be as effective as a full dose, according to new research published December 2 in the open-access journal PLoS Neglected Tropical Diseases. Fractional dosing would enable large-scale vaccination campaigns during epidemics, especially at a time of global vaccine shortages.

In the study, immune responses in patients receiving smaller doses of a meningitis vaccine were comparable to a full dose. The study's findings contributed to a 2007 WHO recommendation that a fractional dosing strategy be utilized in the context of severe vaccine shortages during a meningitis epidemic.

Meningitis epidemics occur nearly every year across a wide swath of sub-Saharan Africa, dubbed the "Meningitis Belt". Outbreaks are caused by specific bacterial strains (primarily Neisseria meningitidis serogroups A and W135), which current vaccines target. Because of global shortages of meningococcal vaccines, the researchers investigated the use of lower doses.

In a 2004 randomized clinical trial of 750 healthy volunteers (2-19 years old) in Uganda, immune response, assessed by serum bactericidal activity (SBA), was measured for 1/5 and 1/10 doses against a full dose. SBA response and safety/tolerability using 1/5 dose were comparable to full dose for three serogroups (A, Y, W135), though not a fourth (C).

Although another measure of immune response, IgG level, was lower for fractional doses, the aim of mass vaccination during epidemics is short-term protection, which is best measured by SBA.

Because of the lack of vaccine producers and publicly financed vaccine stock, current supplies will likely be insufficient in the case of a large-scale epidemic. Efforts are under way to increase production, but this will not be soon enough if a massive epidemic occurs in the coming months as meningitis season nears. If a large-scale outbreak occurs, WHO will need to quickly advise countries on the fractionate strategy before vaccine supplies run out, the authors say.

"In view of the current shortage of meningococcal vaccines for Africa, the use of 1/5 fractional doses should be considered as an alternative in mass vaccination campaigns," the authors say.

Citation: Guerin PJ, Næss LM, Fogg C, Rosenqvist E, Pinoges L, et al. (2008) Immunogenicity of Fractional Doses of Tetravalent A/C/Y/W135 Meningococcal Polysaccharide Vaccine: Results from a Randomized Non-Inferiority Controlled Trial in Uganda. PLoS Negl Trop Dis 2(12): e342. doi:10.1371/journal.pntd.0000342
dx.plos.org/10.1371/journal.pntd.0000342

Source: Public Library of Science

Explore further: Japan sees first local dengue case in over 60 years

add to favorites email to friend print save as pdf

Related Stories

A digital version of you

Mar 12, 2014

When NASA's Mars Rover Opportunity sends a photograph of the alien landscape back to Earth, it relays the information as digital data, a series of ones and zeros that computers assemble into pictures that ...

UNICEF discloses vaccine prices for 1st time

May 29, 2011

UNICEF is for the first time publicizing what drugmakers charge it for vaccines, as the world's biggest buyer of lifesaving immunizations aims to spark price competition in the face of rising costs.

ActHIB vaccine recalled in Japan

Mar 11, 2011

Sanofi Pasteur and Daiichi Sankyo on Friday announced a recall of the ActHIB vaccine in Japan after an "unidentified substance" was found in two syringes.

US cable: Pfizer sought dirt on Nigerian official

Dec 10, 2010

(AP) -- Drug maker Pfizer Inc. hired investigators to uncover "corruption links" to Nigeria's embattled former attorney general in an attempt to stop federal cases over a 1996 drug study, according to a U.S. embassy cable ...

Recommended for you

Girls in Colombian town struck by mystery illness

3 minutes ago

A mystery illness has overwhelmed a small town in northern Colombia as scores of teenage girls have been hospitalized with symptoms that parents fear could be an adverse reaction to a popular vaccine against cervical cancer.

Oral contraceptive equal to antibiotics for acne care

7 hours ago

(HealthDay)—At six months, oral contraceptive pills (OCPs) are comparable to systemic antibiotics for acne management, according to a review published in the September issue of the Journal of the American Ac ...

Photodynamic therapy vs. cryotherapy for actinic keratoses

8 hours ago

Photodynamic therapy (PDT, which uses topical agents and light to kill tissue) appears to better clear actinic keratoses (AKs, a common skin lesion caused by sun damage) at three months after treatment than cryotherapy (which ...

US official warns Ebola outbreak will get worse

10 hours ago

A third top doctor has died from Ebola in Sierra Leone, a government official said Wednesday, as a leading American health official warned that the outbreak sweeping West Africa would get worse before it ...

User comments : 0