Prof Dame Sarah Gilbert says medical science has transformed ambitions for new vaccines.
A lab in Wolverhampton is suspended as 43,000 people in England and Wales are potentially affected.
Some people who took tests in Berkshire earlier this month may have wrongly been given the all-clear.
Other groups have reported higher protection, but the results are still seen as a triumph.
A question everyone's asking: what's my Covid risk? Here's how to find out Pharmacie en Ligne Canada.
Borrowing - which hit a record £22.3bn in October - cannot go on indefinitely, chancellor says.
Farmacia Online con consegna a domicilio: Farmacia online a buon mercato a Roma, Milano, Napoli, Torino, Palermo, Genova, Bologna, Firenze, Catania, Venezia, Verona, Messina, Padova consegna rapida. Acquistare farmaci generici Viagra, Cialis, Levitra, Tadalafil, Vardenafil, Sildenafil, Ivermectina senza ricetta in Italia. Farmacia Online Italiana: Comprare medicinali generici a buon mercato.