Ground-breaking research makes childhood vaccines safe in all
temperatures

Date:
June 8, 2020
Source:
University of Bath
Summary:
A new system for delivering vaccines to children in low-income
nations has taken a vital step forward, thanks to groundbreaking
work.



FULL STORY ========================================================================== Vaccines are notoriously difficult to transport to remote or dangerous
places, as they spoil when not refrigerated. Formulations are safe between 2DEGC and 8DEGC, but at other temperatures the proteins start to unravel, making the vaccines ineffective. As a result, millions of children around
the world miss out on life-saving inoculations.


========================================================================== However, scientists have now found a way to prevent warmed-up vaccines
from degrading. By encasing protein molecules in a silica shell, the
structure remains intact even when heated to 100DEGC, or stored at room temperature for up to three years.

The technique for tailor-fitting a vaccine with a silica coat -- known
as ensilication- was developed by a Bath team in collaboration with the University of Newcastle. This pioneering technology was seen to work in
the lab two years ago, and now it has demonstrated its effectiveness in
the real world too.

In their latest study, published in the journal Scientific Reports, the researchers sent both ensilicated and regular samples of the tetanus
vaccine from Bath to Newcastle by ordinary post (a journey time of
over 300 miles, which by post takes a day or two). When doses of the ensilicated vaccine were subsequently injected into mice, an immune
response was triggered, showing the vaccine to be active. No immune
response was detected in mice injected with unprotected doses of the
vaccine, indicating the medicine had been damaged in transit.

Dr Asel Sartbaeva, who led the project from the University of Bath's
Department of Chemistry, said: "This is really exciting data because it
shows us that ensilication preserves not just the structure of the vaccine proteins but also the function -- the immunogenicity." "This project
has focused on tetanus, which is part of the DTP (diphtheria, tetanus
and pertussis) vaccine given to young children in three doses. Next, we
will be working on developing a thermally-stable vaccine for diphtheria,
and then pertussis. Eventually we want to create a silica cage for
the whole DTP trivalent vaccine, so that every child in the world
can be given DTP without having to rely on cold chain distribution."
Cold chain distribution requires a vaccine to be refrigerated from the
moment of manufacturing to the endpoint destination.

Silica is an inorganic, non-toxic material, and Dr Sartbaeva estimates
that ensilicated vaccines could be used for humans within five to 15
years. She hopes the technology to silica-wrap proteins will eventually
be adopted to store and transport all childhood vaccines, as well as
other protein-based products, such as antibodies and enzymes.

"Ultimately, we want to make important medicines stable so they
can be more widely available," she said. "The aim is to eradicate vaccine-preventable diseases in low income countries by using thermally
stable vaccines and cutting out dependence on cold chain." Currently,
up to 50% of vaccine doses are discarded before use due to exposure to suboptimal temperatures. According to the World Health Organisation (WHO),
19.4 million infants did not receive routine life-saving vaccinations
in 2018.

The Bath research was funded by the Royal Society, Alumni Fund in
University of Bath, specifically the Annett Trust, BBSRC, MRC and ERC.


========================================================================== Story Source: Materials provided by University_of_Bath. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. A. Doekhie, R. Dattani, Y-C. Chen, Y. Yang, A. Smith, A. P. Silve,
F.

Koumanov, S. A. Wells, K. J. Edler, K. J. Marchbank,
J. M. H. van den Elsen, A. Sartbaeva. Ensilicated tetanus
antigen retains immunogenicity: in vivo study and time-resolved
SAXS characterization. Scientific Reports, 2020; 10 (1) DOI:
10.1038/s41598-020-65876-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200608092932.htm

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