Fourth Shot Of Covid-19 Vaccine is Not enough to Prevent Omicron – Research

A recent preliminary study in Israel has shown that the fourth dose of the Covid vaccine is not effective on the Omicron variant and provides only limited defence.

Israel’s Sheba Medical Center has given second booster shots in a trial among its staff and is studying the effect of the Pfizer booster in 154 people after two weeks and the Moderna booster in 120 people after one week, said Gili Regev-Yochay, director of the Infectious Diseases Unit.

These were compared to a control group that did not receive the fourth shot. Those in the Moderna group had previously received three shots of Pfizer’s vaccine, the hospital said.

The clinical trial found that both groups showed increases in antibodies ‘slightly higher’ than following the third vaccine last year. But it said the increased antibodies did not prevent the spread of Omicron.

Dr Regev- Yochay, the director of the hospital’s infection disease unit, noted that the vaccines led to an increase in the number of antibodies a little higher than the third dose”

She further stated that this is not enough for the Omicron variant, noting that the level of antibodies needed to be protected from Omicron variant is probably too high for the vaccine.

She said: ‘Despite increased antibody levels, the fourth vaccine only offers a partial defense against the virus, ‘The vaccines, which were more effective against previous variants, offer less protection versus omicron.’

‘The vaccine, which was very effective against the previous strains, is less effective against the Omicron strain.’

‘We see an increase in antibodies, higher than after the third dose. However, we see many infected with Omicron, who received the fourth dose. Granted, less than in the control group, but still a lot of infections.’

‘The bottom line is that the vaccine is excellent against the Alpha and Delta [variants]. For Omicron, it’s not good enough.‘

Dr. Nahman Ash, director of Israel’s Health Ministry, said the research did not mean the fourth vaccine effort was a mistake.

‘It returns the level of antibodies to what it was at the beginning of the third booster. That has great importance, especially among the older population,’ he told Channel 13 TV.

But he said the research would be considered as authorities debate whether to expand the additional booster campaign to the broader population.