Doctor and senior woman wearing facemasks during coronavirus and flu outbreak. Virus protection. COVID-2019..

Health officials say the H1N1 flu vaccine could be available as early as three weeks from now. And only one dose may be needed for each recipient.

Researchers and vaccine makers had originally expected that a swine flu vaccine would require two doses in order to be effective, but early trials revealed that just one dose of the swine flu was effective within eight to 10 days. This success has allowed health officials to roll out vaccination initiatives much earlier than expected. The original goal of mid-October has been moved up, with the first batch of shots possibly available by the end of September. Widespread vaccinations should begin the first week of October, Bloomberg News reported.

Healthcare workers are among those recommended to receive the vaccine first. Researchers say the side effects of the H1N1  flu vaccine appear to be similar to those of the regular seasonal flu vaccine. But while the swine flu vaccine didn’t cause any serious problems in the clinical trials, researchers readily admit the size of the cohort was too small to detect any rarer side effects. Once the full vaccine rollout begins, health officials will be watching closely for any abnormal responses to the injection.